. they obtain from the activities is very important to the training in their character.A.

问题补充：

. they obtain from the activities is very important to the training in their character.

A. That

B. Which

C. What

D. How

答案：

A. That

B. Which

(答案→)C. What

D. How

解析：考查主语从句。 they obtain from the activities是主语从句，从句的obtain缺少宾语，用what。故选C。