----How unhappy your roommate looks!
----Yes，but he’s not willing to tell me what it is is troubling him.
A. what
B. which
C. as
D. that
网友回答
A. what
B. which
C. as
(答案→)D. that
解析：该题考查特殊疑问词what引导的强调句作tell的宾语，当强调句中有特殊疑问词时应把疑问词放在句子前面。若将该句改为非强调句为: but he’s not willing to tell me what it is troubling him.