diff --git a/src/net/micode/notes/data/Contact.java b/src/net/micode/notes/data/Contact.java
index d97ac5d..ba6c5e6 100644
--- a/src/net/micode/notes/data/Contact.java
+++ b/src/net/micode/notes/data/Contact.java
@@ -24,47 +24,53 @@ import android.telephony.PhoneNumberUtils;
 import android.util.Log;
 
 import java.util.HashMap;
-
-public class Contact {
+//change
+public class Contact {//联系人
     private static HashMap<String, String> sContactCache;
     private static final String TAG = "Contact";
 
+    //定义字符串CALLER_ID_SELECTION
     private static final String CALLER_ID_SELECTION = "PHONE_NUMBERS_EQUAL(" + Phone.NUMBER
     + ",?) AND " + Data.MIMETYPE + "='" + Phone.CONTENT_ITEM_TYPE + "'"
     + " AND " + Data.RAW_CONTACT_ID + " IN "
             + "(SELECT raw_contact_id "
             + " FROM phone_lookup"
             + " WHERE min_match = '+')";
-
+    // 获取联系人
     public static String getContact(Context context, String phoneNumber) {
         if(sContactCache == null) {
             sContactCache = new HashMap<String, String>();
         }
-
+        // 查找HashMap中是否已有phoneNumber信息
         if(sContactCache.containsKey(phoneNumber)) {
             return sContactCache.get(phoneNumber);
         }
 
         String selection = CALLER_ID_SELECTION.replace("+",
                 PhoneNumberUtils.toCallerIDMinMatch(phoneNumber));
+        // 查找数据库中phoneNumber的信息
         Cursor cursor = context.getContentResolver().query(
                 Data.CONTENT_URI,
                 new String [] { Phone.DISPLAY_NAME },
                 selection,
                 new String[] { phoneNumber },
                 null);
-
+			// 判定查询结果
+			// moveToFirst()返回第一条
         if (cursor != null && cursor.moveToFirst()) {
             try {
+            // 找到相关信息
                 String name = cursor.getString(0);
                 sContactCache.put(phoneNumber, name);
                 return name;
+            // 异常
             } catch (IndexOutOfBoundsException e) {
                 Log.e(TAG, " Cursor get string error " + e.toString());
                 return null;
             } finally {
                 cursor.close();
             }
+          // 未找到相关信息
         } else {
             Log.d(TAG, "No contact matched with number:" + phoneNumber);
             return null;