人工将C02含量的浓度加大到多少时,就可将霉菌全部杀死
A.20%
B.40%
C.50%
D.60~70%
E.80~90%
参考答案:E
—The traffic is heavy now, so Mike come late.
—Let’s wait ten more minutes.
A.can
B.need
C.may
D.shall
属于静荷载的是:()
A、作业人员
B、脚手板
C、水泥