原发性慢性肾上腺皮质功能减退症典型体征是（）。
A.皮肤紫纹
B.轻度肥胖
C.皮肤黏膜色素沉着
D.皮肤多汗及低热
E.脉率增快
参考答案：C
— I think it's going to be a big problem.
— Yes, it could be.
— I wonder _____ we can do about it. [ ]
A. if
B. how
C. what
D. that
平流层的特点。
