[例1]—Do you think it’s going to rain over the weekend？
—______.
A.I don’t believe B.I don’t believe it
C.I believe not so D.I believe not
【解析】答案D。“so”可代替某些动词后的宾语从句，但绝不能用it或that。这些常用的动词有：believe，be afraid，expect，hope，imagine，suppose等。例：
—Is she going to the party tonight？
—I think so./I hope so.
其否定有两种：
1.动词用否定结构。
2.用not代替so。如：
—Do you think he will pass the exam？
—I don’t think so./I think not.前者更常用。
错解分析：A项应为I don’t believe so。C项否定也应否定谓语。
解题方法与技巧：根据具体语言环境，正确运用表达观点的方法。
[例2]______for the free ticket，I would not have gone to the films so often.
A.If it is not B.Were it not
C.Had it not been D.If there were to
【解析】答案C。跟过去事实相反的虚拟条件句结构为If+主语+had+过去分词，主语+would/could/might do…当if省略时，将had提主句首，即
Had+主语+过去分词，主语+would/could/might do…
错解分析：
A项不是虚拟语气结构。
B项是跟现在事实相反的虚拟条件句。
D项是跟将来事实相反的虚拟条件句。
[例3]—You ought to have given them some advice.
—______，but who cared what I asked？
A.So it was B.So I ought to have
C.So I did D.So I ought to
【解析】答案B。ought to，want，hope等动词后可省略作宾语的不定式短语，但该宾语若是be动词或动词的完成时，则需在to后加be或have。
—Are you a soldier？
—No，but，wish to be（a soldier）.
[例4]The research is so designed that once______nothing can be done to change it.
A.begins B.having begun C.beginning D.begun