根据使用地区的气候条件和季节来确定液压油，一般夏季选用（）机油冬季选用20#机油为宜。
A.0#
B.20#
C.30#
D.40#
参考答案：D
在一个宴会上，每个客人都免费获得一份冰淇淋或一份水果沙拉，但不能同时获得二者．在该宴会上，60%的客人获得了冰淇淋，并且免费提供的冰淇淋和水果沙拉共120份。那么有（）客人能获得水果沙拉。
A.48
B.72
C.52
D.84
He is a little bit mysterious these days. Nobody in our company knows exactly.
A．what he is working on
B．what is he working on
C．what did he work on
D．what was he working on
