Question

19．李华帮妈妈做完家务才开始复习功课．
Li Huadidn't begin going over the lesson until she helped her mother finish doingthe housework．

Answer 1

分析 didn't begin going over the lesson until she helped her mother finish doing．

解答 答案：didn't begin going over the lesson until she helped her mother finish doing．这里是说过去的事情用一般过去时，这里表示直到…才用not…until…，主句是李华才开始复习功课，主语Li Hua，开始做某事用begin doing sth，复习功课go over the lesson，begin是实意动词借助于did构成否定，故Li Hua didn't begin going over the lesson，until引导时间状语从句，主语用she代替，帮助某人做某事用help sb do sth，他妈妈her mother，完成做某事finish doing sth，做家务do housework，故until she helped her mother finish doing，故答案是didn't begin going over the lesson until she helped her mother finish doing．

点评 "not…until""意思是："直到…才…"表示在这个界限之前一直没有发生这个动作You can't leave until I come back．．直到我回来你才可以离开"until""意思是："直到…"表示这个动作一直延续到这个界限出现时．   （易错点：将"not…until""句型翻译成了否定句，如上句：直到我回来你不可以离开×）