on time is good manners.
[ ]
A. Be
B. Is
C. Are
D. Being
答案:D
If you want to buy some pears, you can go to the _____________. [ ]
A. bookstore
B. fruit store
C. pet shop
钢筋冷拉时,如果采用应力控制法,当冷拉应力为σ,冷拉率为S,下列哪种情况是合格的?()
A.S达控制值,σ未达控制值
B.σ达控制值,S超过规定值
C.S未达控制值,σ达控制值
D.σ未达控制值,S未超过规定值