答：
第一题，C，没异议。
第二题，是A，祈使句+and+陈述句（will +V), 不少TX以为是动名词作主语，选了C，错！
第三题有争议。
3.Tom said it was at least five years since he___a good drink.
A:enjoyed B:was enjoying C:had enjoyed D:would enjoy.
答：本题考从句中的时态。
为增加难度，为题目创新，出题者加上了一个Tom said, 从而在宾语从句中又出现了时间状语从句。
先考查简单的：
It is at least five years since he ______a good drink.
A:enjoyed B:was enjoying C:had enjoyed D:would enjoy.
答：A
译：他至少有五年没有痛痛快快地唱酒了。
析：本题句改自《Longman》上的一个经典例句：
It's been years since I enjoyed myself so much as last night.
我已经有很多年没有象昨晚那么痛快了。
由于其句意翻译与众不同，后来衍生出好多这样的题句。主要是讲since从句的谓语是延续性动词时的翻译问题，不在此展开。
我想说的是：It has been some time since sth. happened.是一个很有用的句型。
意为：自从某件事性发生以来，到现在已经有多久了。since表示“自。。。以来，到现在为止”，主句用现在完成时态（这里的has been)与我们以前学习的现在完成时态语法知识相符合。
值得注意的是：现在这个句型已经演变为：
It is some time since sth. happened. 了。
原题句=It has been at least 5 years since he enjoyed a good drink (last time).
意思是说：自从他上（一次）痛痛快快地唱酒以来，到现在为止，已经有5年了。直到说话的那一刻，他才又这么痛快的喝酒。他自己是这么说的：
He said, "It is (=has been) at least 5 years since I enjoyed a good drink."
现在，将它转述一下，（改为间接引语，也就是宾语从句）
--> He said that it was (=had been) at least 5 years since he enjoyed a good drink.
请注意：主过从过，时态一致，直接引语变成间接引语时，要变成过去时态的是主句中的谓语（is-->was, has been-->had been) ，不是将since 从句中的过去时态变成过去完成时态。
请大家复习一下别的带有since 从句的现在完成时的句子变成间接引语时的时态变化：
sb. has done sth. since sth. happened.--> He said that he had done sth. since sth. happened.
是指“自从（过去）某事发生以来，到他说话时为止（另一过去时间），他一直在做某事。
例如：He said he had been a teacher since he graduated from XX university. (since 1997)
他说自从XX大学毕业以来（自从1997年以来）他一直当教师。
since从句还是一般过去时吧？！
所以本题的“正确”答案应该是A。
不过，我很可能不得分。选C的TX很可能得分。问楼主去。
如果标准答案是C，我估计出题者自己都没有真正弄懂这个句型。
追问可是正确答案是C......我们老师说是过去的过去，用过去完成时......
追答不是“正确”答案，是参考答案。是“标准”答案。我上面已经指出了。
那是根据主过从过，时态后退，机械变过来的。is-->was, enjoyed-->had enjoyed
须知It is some time since sth. happened 是It has been some time since sth. happened变过来的。
而后面这句话变成间接引语时，如果机械地改时态，是has been-->had been, happened--> had happened
--> sb. said that it had been some time since sth. had happened 也对吧。
但是sb. said that it had been some time since sth. happened 比上一句更好，因为两个过去完成时，并不能表示那一个更前
从应试来看，选C比较保险。