Question

it was the training __he had as a young man____made him such a good engineer.

A.what;that B.that;what C.that;which D.which;that
选什么？

Answer 1

D
第一个定语从句，先行词the training ,关系代词在从句中充当had的宾语。
第二个是强调句型It was ... that...

Answer 2

B.that;what

Answer 3

D
it was the training __he had as a young man____made him such a good engineer.可转化为
the training which he had ( as a young man相当于插入语，可省略不看)made him such a good engineer。
所以这里有个强调句型It was ... that... 。第一个which特指他接受的那个训练。