下列各组数中,相等的一组是[ ]
A.+32与+22
B.﹣23与(﹣2)3
C.﹣32与(﹣3)2
D.3×22与(3×2)2
B.
Tom got all A's _____ he spent most of his time studying. [ ]
A. if
B. before
C. because
D. although
施工技术准备时,选择施工机械时应注意什么?