巴豆霜要求含脂肪油量应为()。
A.3%~5%
B.8%~10%
C.18%~20%
D.20%~30%
参考答案:C
------ Have you seen your nephew lately?
------ Yes, in fact, I saw him yesterday. I ______ him for three years.
A.haven’t
B.didn’t
C.hadn’t
D.don’t
造成昼夜长短变化的主要因素是
① 地球的公转
②地球的自转
③黄赤交角的存在
④地方时的不同[ ]
A.①
B.②
C.③
D.④