diff --git a/functions/DNSSEC.php b/functions/DNSSEC.php
new file mode 100644
index 0000000..de49dc6
--- /dev/null
+++ b/functions/DNSSEC.php
@@ -0,0 +1,47 @@
+<?php
+
+class DNSSEC {
+    public function algorithmDesc($id) { // 获取算法类型
+        switch ($id) {
+            case '1':
+                return 'RSA/MD5';
+            case '3':
+                return 'DSA/SHA1';
+            case '5':
+                return 'RSA/SHA-1';
+            case '6':
+                return 'DSA-NSEC3-SHA1';
+            case '7':
+                return 'RSASHA1-NSEC3-SHA1';
+            case '8':
+                return 'RSA/SHA-256';
+            case '10':
+                return 'RSA/SHA-512';
+            case '12':
+                return 'GOST R 34.10-2001';
+            case '13':
+                return 'ECDSA Curve P-256 with SHA-256';
+            case '14':
+                return 'ECDSA Curve P-384 with SHA-384';
+            case '15':
+                return 'Ed25519';
+            case '16':
+                return 'Ed448';
+        }
+    }
+
+    public function digestDesc($id) { // 获取摘要类型
+        switch ($id) {
+            case '1':
+                return 'SHA-1';
+            case '2':
+                return 'SHA-256';
+            case '3':
+                return 'GOST R 34.11-94';
+            case '4':
+                return 'SHA-384';
+        }
+    }
+}
+
+?>
diff --git a/functions/Domain.php b/functions/Domain.php
index fa1f23b..8bc4adc 100644
--- a/functions/Domain.php
+++ b/functions/Domain.php
@@ -76,6 +76,17 @@ class Domain { // 域名相关功能
         );
     }
 
+    public function getSubTld($tld) {
+        $db = new SqliteDB($this->tldDB);
+        $res = $db->query('SELECT record FROM `list` WHERE tld="' . $tld . '";');
+        while ($row = $res->fetchArray(SQLITE3_ASSOC)) {
+            if ($row['record'] !== $tld) {
+                $subTld[] = $row['record'];
+            }
+        }
+        return $subTld;
+    }
+
     public function icpTldInfo($tld) { // 查询TLD的ICP信息
         $db = new SqliteDB($this->tldDB);
         $info = $db->query('SELECT * FROM `icp` WHERE tld="' . $tld . '";');
diff --git a/main.php b/main.php
index a8d5f4e..5cf0cab 100644
--- a/main.php
+++ b/main.php
@@ -5,6 +5,7 @@ require_once 'route.php';
 require_once 'functions/DNS.php';
 require_once 'functions/Curl.php';
 require_once 'functions/Domain.php';
+require_once 'functions/DNSSEC.php';
 require_once 'functions/Punycode.php';
 require_once 'functions/SqliteDB.php';
 require_once 'functions/RedisCache.php';
diff --git a/models/tldQuery.php b/models/tldQuery.php
index cbacd56..0bf6ba2 100644
--- a/models/tldQuery.php
+++ b/models/tldQuery.php
@@ -1,14 +1,14 @@
 <?php
 
-class tldQueryEntry {
-    private $tldDB = './db/tldInfo.db';
+class tldQueryEntry { // TLD信息查询入口
+    private $tldDB = './db/tldInfo.db'; // TLD信息数据库
 
-    private function getTldInfo($tld) {
+    private function getTldInfo($tld) { // 获取TLD详细信息
         $db = new SqliteDB($this->tldDB);
         $res = $db->query('SELECT * FROM `iana` WHERE tld="' . $tld . '";');
         $info = $res->fetchArray(SQLITE3_ASSOC);
-        if (!$info) { return null; }
-        $info['manager'] = json_decode(base64_decode($info['manager']), true);
+        if (!$info) { return null; } // 查无该TLD
+        $info['manager'] = json_decode(base64_decode($info['manager']), true); // Base64解码 + JSON解码
         $info['admin_contact'] = json_decode(base64_decode($info['admin_contact']), true);
         $info['tech_contact'] = json_decode(base64_decode($info['tech_contact']), true);
         $info['nameserver'] = json_decode(base64_decode($info['nameserver']), true);
@@ -16,14 +16,14 @@ class tldQueryEntry {
         return $info;
     }
 
-    private function genMessage($info) { // 生成返回消息
-        $msg = '`' . $info['tld'] . '` `(` `' . $info['type'];
-        if ($info['active'] === 'yes') {
+    private function genMessage($info, $icp, $subTld) { // 生成返回消息
+        $msg = '`' . (new Punycode)->decode($info['tld']) . '` `(` `' . $info['type'];
+        if ($info['active'] === 'yes') { // TLD是否有效解析
             $msg .= '` `)`' . PHP_EOL;
         } else {
             $msg .= ' not active` `)`' . PHP_EOL;
         }
-        if (count($info['manager']) !== 0) {
+        if (count($info['manager']) !== 0) { // 域名管理者信息
             $msg .= '*Manager*' . PHP_EOL;
             foreach ($info['manager']['name'] as $row) {
                 $msg .= '  ' . $row . PHP_EOL;
@@ -32,7 +32,7 @@ class tldQueryEntry {
                 $msg .= '  _' . $row . '_' . PHP_EOL;
             }
         }
-        if (count($info['admin_contact']) !== 0) {
+        if (count($info['admin_contact']) !== 0) { // 域名管理员联系人
             $contact = $info['admin_contact'];
             $msg .= '*Administrative Contact*' . PHP_EOL;
             $msg .= '  ' . $contact['name'] . PHP_EOL;
@@ -50,7 +50,7 @@ class tldQueryEntry {
                 $msg .= '  Fax: _' . $contact['fax'] . '_' . PHP_EOL;
             }
         }
-        if (count($info['tech_contact']) !== 0) {
+        if (count($info['tech_contact']) !== 0) { // 域名技术支持联系人
             $contact = $info['tech_contact'];
             $msg .= '*Technical Contact*' . PHP_EOL;
             $msg .= '  ' . $contact['name'] . PHP_EOL;
@@ -68,7 +68,7 @@ class tldQueryEntry {
                 $msg .= '  Fax: _' . $contact['fax'] . '_' . PHP_EOL;
             }
         }
-        if (count($info['nameserver']) !== 0) {
+        if (count($info['nameserver']) !== 0) { // 域名NS服务器信息
             $nameserver = $info['nameserver'];
             $msg .= '*Name Servers*' . PHP_EOL;
             foreach ($nameserver as $host => $ips) {
@@ -78,52 +78,28 @@ class tldQueryEntry {
                 }
             }
         }
-        if (count($info['dnssec']) !== 0) {
+        if ($subTld !== null) { // 输出次级顶级域
+            $msg .= '*Sub TLD*' . PHP_EOL;
+            foreach ($subTld as $tld) {
+                $msg .= '  `' . (new Punycode)->decode($tld) . '`' . PHP_EOL;
+            }
+        }
+        if (count($info['dnssec']) !== 0) { // 域名DNSSEC状态
             if ($info['dnssec']['type'] === 1) { // 正常DNSSEC
                 $msg .= '*DNSSEC*' . PHP_EOL;
                 foreach ($info['dnssec']['ds'] as $ds) {
                     $msg .= '  *Tag: ' . $ds['tag'] . '*' . PHP_EOL;
-                    if (strlen($ds['hash']) === 64) {
+                    if (strlen($ds['hash']) === 64) { // SHA256
                         $msg .= '    `' . substr($ds['hash'], 0, 32) . '`' . PHP_EOL;
                         $msg .= '    `' . substr($ds['hash'], -32) . '`' . PHP_EOL;
-                    } else if (strlen($ds['hash']) === 40){
+                    } else if (strlen($ds['hash']) === 40){ // SHA1
                         $msg .= '    `' . substr($ds['hash'], 0, 32) . '`' . PHP_EOL;
                         $msg .= '    `' . substr($ds['hash'], -8) . '`' . PHP_EOL;
                     }
-                    $msg .= '    Algorithm: _' . $ds['algorithm'];
-                    if ($ds['algorithm'] === '1') {
-                        $msg .= ' (RSA/MD5)';
-                    } else if ($ds['algorithm'] === '3') {
-                        $msg .= ' (DSA/SHA1)';
-                    } else if ($ds['algorithm'] === '5') {
-                        $msg .= ' (RSA/SHA-1)';
-                    } else if ($ds['algorithm'] === '6') {
-                        $msg .= ' (DSA-NSEC3-SHA1)';
-                    } else if ($ds['algorithm'] === '7') {
-                        $msg .= ' (RSASHA1-NSEC3-SHA1)';
-                    } else if ($ds['algorithm'] === '8') {
-                        $msg .= ' (RSA/SHA-256)';
-                    } else if ($ds['algorithm'] === '10') {
-                        $msg .= ' (RSA/SHA-512)';
-                    } else if ($ds['algorithm'] === '12') {
-                        $msg .= ' (GOST R 34.10-2001)';
-                    } else if ($ds['algorithm'] === '13') {
-                        $msg .= ' (ECDSA Curve P-256 with SHA-256)';
-                    } else if ($ds['algorithm'] === '14') {
-                        $msg .= ' (ECDSA Curve P-384 with SHA-384)';
-                    } else if ($ds['algorithm'] === '15') {
-                        $msg .= ' (Ed25519)';
-                    } else if ($ds['algorithm'] === '16') {
-                        $msg .= ' (Ed448)';
-                    }
-                    $msg .= '_' . PHP_EOL;
-                    $msg .= '    Digest type: _' . $ds['digest'];
-                    if ($ds['digest'] === '1') {
-                        $msg .= ' (SHA-1)';
-                    } else if ($ds['digest'] === '2') {
-                        $msg .= ' (SHA-256)';
-                    }
-                    $msg .= '_' . PHP_EOL;                    
+                    $msg .= '    Algorithm: _' . $ds['algorithm'] . ' ('; // 算法类型
+                    $msg .= (new DNSSEC)->algorithmDesc($ds['algorithm']) . ')_' . PHP_EOL;
+                    $msg .= '    Digest type: _' . $ds['digest'] . ' ('; // 摘要类型
+                    $msg .= (new DNSSEC)->digestDesc($ds['digest']) . ')_' . PHP_EOL;                    
                 }
             } else if ($info['dnssec']['type'] === 3) { // 启用DNSSEC 但未部署DS记录
                 $msg .= '*DNSSEC:* signed, but without DS record.' . PHP_EOL;
@@ -131,28 +107,53 @@ class tldQueryEntry {
                 $msg .= '*DNSSEC:* unsigned' . PHP_EOL;
             }
         }
-        if ($info['website'] != '') {
+        if ($icp !== null) { // ICP备案信息
+            $msg .= '*ICP Detail*' . PHP_EOL;
+            $msg .= '  管理机构: ';
+            if ($icp['org'] === '空') {
+                $msg .= '未知' . PHP_EOL;
+            } else {
+                $msg .= $icp['org'] . PHP_EOL;
+                $msg .= '  机构主页: ';
+                foreach ($icp['site'] as $site) {
+                    $msg .= '`' . $site . '` ';
+                }
+                $msg .= PHP_EOL;
+            }
+        }
+        if ($info['website'] != '') { // 所有者主页
             $msg .= '*Website:* ' . $info['website'] . PHP_EOL;
         }
-        if ($info['whois'] != '') {
+        if ($info['whois'] != '') { // Whois服务器信息
             $msg .= '*Whois Server:* `' . $info['whois'] . '`' . PHP_EOL;
         }
-        $msg .= '*Registration date:* _' . $info['regist_date'] . '_' . PHP_EOL;
-        $msg .= '*Record last updated:* _' . $info['last_updated'] . '_' . PHP_EOL;
+        $msg .= '*Registration date:* _' . $info['regist_date'] . '_' . PHP_EOL; // 注册日期
+        $msg .= '*Record last updated:* _' . $info['last_updated'] . '_' . PHP_EOL; // 最后更改时间
         return $msg;
     }
 
     public function query($rawParam) { // TLD数据查询入口
+        if ($rawParam == '' || $rawParam === 'help') {
+            tgApi::sendMessage(array( // 发送使用说明
+                'parse_mode' => 'Markdown',
+                'text' => '*Usage:*  `/tld top-level-domain`',
+            ));
+            return;
+        }
         if (substr($rawParam, 0, 1) !== '.') { // 补上.
             $rawParam = '.' . $rawParam;
         }
+        $rawParam = (new Punycode)->encode($rawParam);
         $info = $this->getTldInfo($rawParam);
-        if (!$info) {
-            tgApi::sendMarkdown('`' . $rawParam . '`' . PHP_EOL . 'TLD not found');
+        if (!$info) { // 查无该TLD
+            $rawParam = (new Punycode)->decode($rawParam);
+            tgApi::sendMarkdown('`' . $rawParam . '`' . ' not found');
             return;
         }
+        $icp = (new Domain)->icpTldInfo($rawParam); // 查询ICP信息
+        $subTld = (new Domain)->getSubTld($rawParam); // 查询次级域信息
         tgApi::sendMessage(array(
-            'text' => $this->genMessage($info),
+            'text' => $this->genMessage($info, $icp, $subTld),
             'parse_mode' => 'Markdown', // Markdown格式输出
             'disable_web_page_preview' => 'true' // 不显示页面预览
         ));