It is so wet there the trees are extremely tall some measuring over 90 meters.A. whatB.

问题补充：

It is so wet there the trees are extremely tall, some measuring over 90 meters.

A. what

B. which

C. that

D. why

答案：

A. what

B. which

(答案→)C. that

D. why

解析：考查强调句型。强调句型：It is/was 被强调成分that 其它成分。去掉it is/was that，句子仍然成立。