My mother ______ have dinner at home. [ ]
A. isn't
B. don't
C. doesn't
D. aren't
答案:C
要做一个不带盖的圆柱形铁皮水桶,底面直径6分米,高5分米,做这个水桶至少需要多少铁皮?
※ [18~20] .( 3 )
A. .
B. .
C. .
D. .