He can go with you, but I ______. [ ]
A. am not
B. can't
C. don't
D. must
答案:B
(2012)岩土工程勘察等级分为:()
A.2级
B.3级
C.4级
D.5级
固体润滑材料没有粘度变化,二硫化钼能在()下润滑。
A.-120℃
B.-140℃
C.-160℃
D.-180℃