尿素装置的二氧化碳压缩机采用（）驱动。
A.饱和蒸汽
B.过热蒸汽
C.电
D.以上都不是
参考答案：B
Before sitting for the entrance examination for post-graduate students, many candidates try to familiarize themselves with the formula of the exam by doing () tests.
A. imitated
B. simulated
C. stimulated
D. exemplary
将棱长4厘米的正方体分成若干个棱长1厘米的小正方体，这些小正方体的表面积之和比原来正方体的表面积增加（ ）平方厘米
