必修四 UNITS 3～5 1．...until...“直到……时候”；not...until...“直到……才……” The meeting was put off until ten o’clock.会议推迟到十点钟。 句型公式妙笔生花 Not until all the fish died in the river did the villagers realize how serious the pollution was.(倒装句) 等到湖里的鱼全死光了，村民们才意识到污染是多么严重。 2．unless...“除非，如果不……”(＝if...not) I won’t attend his birthday party unless invited(＝unless I am invited)．除非被邀请，否则我不会去参加他的生日晚会。 3．主语＋be doing...when...“正在做某事这时……” I was walking along the river when I heard a drowning boy cry for help. 我正在河边散步，这时我突然听到一个落水男孩求救。 4．主语＋be about to do...when.../主语＋be on the point of(doing)．..when...“刚要……这时……” I was about to leave when it began to rain.我刚要离开，这时下雨了。 5．主语＋had done...when...“刚做完……这时……” I had just finished my exam paper when the bell rang，announcing the class was over.我刚做完作业，下课铃响了。 本部分内容讲解结束 按ESC键退出全屏播放