砌筑作业一级分包企业具有初级上砖瓦、抹灰技术工人不少于()人。
A.50
B.30
C.60
D.40
参考答案:A
曲线y=xex+2x+1在点(0,1)处的切线方程为______.
I've always dreamt ____coming to China and now my dream has come____. [ ]
A. about; real
B. of; true
C. out; truth
D. from; truly