1. I really don‘t konw ___.they are all very beautiful. A.which ong should choose B.which one to choose C.to choose which one 答案选B：“疑问词+不定式”结构相当于一个名词短语，做know的宾语。该结构的具体解释请参看我的另一答案：
http://zhidao.baidu.com/question/57169770.html2.Mr paul is a good teacher He often has a strange way___making hia classes ____ A.of; live B.to ;live C.of; lively D.to ;living 答案选C：固定结构the way of doing sth或the way to do sth “做某事的方法”； lively adj. 生动活泼的3.No one enjoys ___ at. A laughing B to laugh C to be laughed D deing laughed 答案选D：enjoy doing sth，排除BC；而句意是“没有人喜欢被嘲笑”，后面用被动，所以就变成了enjoy being done。4.Each of our English classes begins with ___talk. A.an every day B.daily C.an everyday D.five-minute 答案选C：talk在此句是可数名词，需要冠词，排除BD；everyday adj. 每日的，日常的；every day是个副词短语，在句中充当时间状语，而不能充当定语去修饰名词。5.Mable was ___ill__she had to be taken to hospital at once. A.so;so B.so;that C.such;that D.such a;that答案选B：固定句型so...that... “如此...以致于...”；而such是形容词，要修饰名词，但ill不是名词；so才是程度副词，修饰形容词和副词（象very一样，ill是个形容词）。