问题补充：
she is not so cheerful she used to be?
A. How is it that; as
B. Why is it that; what
C. Is it why; that
D. How it is what; as
答案：
(答案→)A. How is it that; as
B. Why is it that; what
C. Is it why; that
D. How it is what; as
解析：解析：句意：她怎么不像过去那样高兴了呢？强调句的特殊疑问句式：特殊疑问词＋is/was it that＋原句剩余部分。D项中的what不正确，故选A。
