问题
选择题
A nursing home in Tianjin has opened offering ________ the owners are describing as facilities as good as a fivestar hotel.
A．which
B．how
C．what
D．that
答案
答案：C
句意：天津一家养老院开业了，业主宣称提供与五星级酒店一样好的设施。空处引导宾语从句，在从句中作动词describe的宾语，故应用what。
则所生成到旋转曲面的方程分别是（）。