第15题: [单项选择]Despite much research, there are still certain elements in the life cycle of the insect that ______ not fully understood. A. are B. were C. is D. was 参考答案:A 答案解析:这里由引导的定语从句修饰复数名词elements,所以定语从句中的that代替的复数意义的名词,其谓语应该用复数形式;这里谈到的是现实存在的事实,排除B项。
第17题:[单选题]How many liaisons of sound are there in the sentence "I called you half an hour ago"? A.one B.two C.three D.four 参考答案:D 考查连读。liaison意为“连音”,在同一个意群里,如果相邻两词中的前一个词是以辅音结尾,后一个词是以元音或半元音,特别是/i/开头,就要将前后两个音拼起来连读。本句中called~vou,half~an,an~hour,hour~ago均需要连读,即I called~you half~an~hour~ago,故选D。