As soon as he had hung up, he went over to the workmen and told them that if a policeman ordered them to go away, they were not to taken him seriously. 我知道这是个虚拟语气，但根据语法书的规定 从句ordered them用过去式，主句应该是would 加动词原形才对，为什么这里用 were not to taken him ？
第一道题，if he hadn't had a flat tire=had he not had a flat tire。 虚拟语气中，条件句里有had， should， 或were的，都可以把条件句里的if去掉，把这三个词提前到主语前面(详细材料百度一下）。答案A，B，C中，B的flatten用法错误，一般用法有sb. flattens sth.或者sth. flattens, 没有sth. flattens itself，而且后面应该是not，不会是no。C的结构是“某物发生了”，也没有这种用法，happen的主语应该是“某事”。D是时态问题。 第二十五道题，it's aboutime/it's high time/it's time sb. did sth. 指“（某人）到了该做某事的时候了，这里did是虚拟语气，你可以把它当固定句式背起来，写作的时候也可以用。