测定水泥凝结时间时,当试针沉至距底板(),即为水泥达到初凝状态。
A.2mm±1mm
B.4mm±1mm
C.6mm±1mm
参考答案:B
Rather than _____ at home I’d prefer ________out to get close to ________nature.
A.stay; go; the
B.to stay; go; /
C.stay; to go; /
D.to stay; to go; the
涂装车间一般采用板式换热器。