some teenagers don't realize is difficult life can be after they get addicted to drugs.
A. What; what a
B. That; how
C. What; how
D. That; what
网友回答
A. What; what a
B. That; how
(答案→)C. What; how
D. That; what
解析：C 考察主语介词和表语从句。第一空使用what引导主语从句，what在主语从句作为realize的宾语，第二空选用how引导表语从句，how修饰形容词difficult。