— Have you got any particular plans for the coming holiday?

— Yes. ________, I'm going to visit some homes for the old in the city. [    ]

A. If ever  

B. If busy

C. If anything  

D. If possible

根据《水工建筑物地下开挖工程施工技术规范》(DL/T5099-1999)，相向开挖的两个工作面相距()时，应停止一方工作，单向开挖贯通，

A.15m 

B.12m 

C.10m 

D.8m