The accident happened ______ a cold winter morning.[ ]
A. in
B. on
C. at
D. of
答案:B
My English is poor, but _____ students laugh _____ me. [ ]
A. a little; at
B. a few; at
C. few; at
D. little; in
湿法安装大理石时,基层面到大理石表面距离不小于______。
A.2cm
B.5cm
C.10cm
D.无要求