______ is surprising to us is that Tom, for ______ English was once boring, can speak English f...

______ is surprising to us is that Tom, for ______ English was once boring, can speak English f...

B

试题分析：通过分析句子结构，可知这个句子中包含一个主语从句，和一个非限制性定语从句。且引导词在主语从句中作主语，表示“什么”的含义，故用what。介词 + 关系代词引导的定语从句，指人只能用whom。 点评：解答这类题，首先要确定从句是什么从句，然后依据相应的语法规则答题。名词性从句中引导词的确定，要看它在名词从句中作什么成分，有什么实际意义。定语从句中关系词的确定，要看它在定语从句中作什么成分。当引导词在定语从句中作介词的宾语时，往往可以把介词放在关系代词之前，构成“介词 + 关系代词（whom / which）”结构。做这类考题时，有以下三个注意事项。1. “介词 + 关系代词”引导定语从句时，关系代词只有whom（指人），which（指物）和whose（表所有）。注意不能用who或that，关系代词也不可省略。如：Do you know the girl with whom the English teacher talked just now?  你认识刚才跟英语老师谈话的那个女孩儿吗？2. 关系副词可以用“介词 + 关系代词”来替换。其中，when =" at" / in / on + which; where =" at" / in / on + which; why =" for" which；而关系代词whose常可用“of + which / whom”来替换。如：The house whose doors are green is an office building. =" The" house of which the doors are green is an office building. 门是绿色的那座房子是办公楼。 3. 含有固定搭配的动词短语，由于其关系紧密，不宜拆分，所以不能将介词置于关系代词之前。这类动词短语有 look after, take care of, listen to, look at, look into, come across, look forward to, break into等。