“龙生龙，凤生凤”这一俗语说明了在自然界中普遍存在着：[ ] A．遗传现象 B．

仓库是保管、储存物品的建筑物和场所的总称。从现代物流系统的角度来看，仓库也是从事包装、分拣、流通加工等物流作业活动的物流节点设施。

— Is the meeting held in Room 302 or 303?

— It should be 302.But I hear that it________till tomorrow.[      ]

A. was put off 

B. will put off

C. has been put off  

D. is put off

The bus hit the huge stone by the road heavily _________ he could stop it.

A. after                B. before           C since             D. until

什么是主麻？

沟槽在管道敷设完毕应尽快回填，一般分为三个步骤。