生产矿井每延伸一个新水平,应进行()次煤尘爆炸性实验。
A、1
B、2
C、3
D、不少于1次
参考答案:A
已知直线l:2ax+ty+3a=0(t≠0,a∈R)经过点(1,-1),求直线l的倾斜角α(结果精确到1°)
The Shanghai Expo Site covers a total area of 5.28 sq km, ______12 pavilion groups, of _____ Zone A hosts China Pavilion, and other national Pavilions for Asian countries except Southeast Asian ones.
A.included, who
B.including, which
C.included, which
D.including, what