1.Moreandmorepeoplehaverealizedwewon'thavecleanerwatertodrinkunlesssomething[]soon.A.wasdoneB.willbedoneC.tobedoneD.isdone(为什么选D不选B）2.EveryoneexpectTomandJack[]therewhenthemeetingbegan.A.wasB.isC.were

Question

1.More and more people have realized we won't have cleaner water to drink unless something[ ]soon.
A.was done B.will be done C.to be done D.is done
(为什么选D不选B）
2.Everyone expect Tom and Jack[ ]there when the meeting began.
A.was B.is C.were D.are
（为什么选A不选D）
3.-Do you know Jack well?
-Certainly!We[ ]friends since ten years ago.
A.were B.have made C.have become D.have been
(为什么选D不选C）
4.-[ ]
-Thanks.I certainly will.
A.Happy birthday to you.
B.Help yourself to some fish.
C.Please remember me to your family.
D.Please don't be late again.
(为什么选C）

Answer 1

我觉得楼上有些说得并不太正确
第二题everyone是主句的主语,而was针对的主语是expect后引导的从句中的主语Tom and Jack,而为什么是用was是因为此从句是个虚拟语气,expect后跟的从句也通常是用虚拟语气.全句的意思是大家都期望在会议开始的时候Tom and Jack在那里（但是其实他们并不在那里,所以用虚拟语气）.
第三题为什么选D不选C是因为become是个瞬间动词,后面跟了一个时间段状语ten years,所以不能用become,要用been表示状态.也可以从意思上来选择,如果选become那么意思就是我们在自从十年前就一直成为朋友（而是朋友是不能一直成为的,成为朋友只是一个瞬间的动作,比如交朋友,不能是十年一直处在交朋友这个状态的）,所以正确的意思是我们从十年前就是朋友了,been表状态