1.I’ll take down your name and address in case you ______ as a witness.
A.are needed B.need C.will be needed D.will need
2.Vegetables are cheap______ when they are in season.
A.buying B.to buy C.to be bought D.to buy them
3.Gone _____ the Chinese people were in great lack of food,money, comfort and enough housing.
A.the days when B.are the days when
C.have the days when D.the days have when
看看答案吧：
1.C 此句译为“我将记下你的姓名和地址，以防万一需要你作证”,这是被动语态的基本用法,“我”或“别的什么人”需要“你”作证人,但没必要指出来,因为这里强调的是动作的承受者,所以用将来时的被动语态.
2.B 当不定式作表语(或宾补)形容词的状语,又与句中的主语(或宾语)有逻辑上的动宾关系时,虽然不定式有被动意义,但只能用主动形式.eg:Some books are interesting to read ,but boring to learn有些书读起来很有趣,但学起来很枯燥.
3.B 此句译为“中国人粮食极其匮乏，经济拮据，生活不安逸，住房又紧缺的日子已经一去不复返” ,如果过去分词是不及物动词,这个动词已经是形容词化了的分词,则为系表结构,这里gone提前,用的倒装结构.