I did all the things（A ）was possible to do to finish the work on time but in vain.
A,IT B,THATC,THISD,WHICH
详细解释！！
要选B我还用问哪！！！
既然all the things是从句的主语，那谓语不该是were吗？
选A是正确的I did all the things it was possible to do to finish the work on time but in vain.to do 不定式做后置定语修饰thingsit was possible 是插入语先看这个句子：She， I think， has no feeling for your trouble. 你能说She, who I think, has no feeling for your trouble 吗显然没有这么说的下面分析一下it was possible 并不是一个定语从句，而是插入语成分，它作为一个整体插入在句子中，不会影响句子
A不对，选B,that引导的定语从句，指代先行词“all the things”先行词是不定代词或者先行词被不定代词所修饰时， 关系代词通常只用that， 不用which。例如：
① That’s all that I know. 我知道的就这些。
② Is there anything that you want t
