受压构件的承载力主要取决于混凝土,因此采用较高强度等级的混凝土是经济合理的。
参考答案:对
George would certainly have attended the meeting,__________.
A.if he didn’t get a flat tire
B.if the flat tire hadn’t happened
C.had he not had a flat tire
D.had the tire not flattened itself
本书,甲看完要10天,乙看完要15天。
(1)写出甲、乙看书的时间比,并化简。
(2)写出甲、乙看书的速度比,并化简。