F
【点拨】Unless unnecessary是Unless it is unnecessary的省略, 意为“除非没必要, 如 果不是没必要”, unless等于if not, 后面用含有否定意义的unnecessary, 相当于双重否 定, 与下句矛盾。unless necessary意为“如果没必要, 除非有必要”, 与下句符合。
【点拨】when是并列连词, 意为“这时”, 而且从句动词多为短暂 性动词。while引导时间状语从句, 谓语动词为持续性动词。break down是短暂性动词短语, 因此不用while。
2. 如果没必要, 你最好不要查字典。 ①Unless unnecessary, you’d better not refer to the dictionary. ( ②Unless necessary, you’d better not refer to the dicti点睛(用本单元学过的词汇补全下文)
a variety of We have __________( 各种各样的 ) accidents in our daily life, for example,
choking falling ill _______(窒息), ________( 生病)suddenly, ____( 皮肤)burns and drinking ______(毒 skin 药 )by mistake. It is ____(至关重要的)to givepoison _______(急救)and call an __________ ambulance vital first aid (救护车). If a person is _______(受伤)and ________(流血), we should use a clean injured bleeding ________(绷带)to cover the ______( 伤口)around ______(坚固地 )and _____(使 injury bandage 用)________(压力)to the bleeding point. If the injured are ________( 治疗)correctly pressure apply firmly and in time, it will _________________(起作用 ). treated make a difference
