Most of the local restaurants were fully booked more than a month _____.[ ]

A. in return  

B. in case

C. in advance  

D. in time

低碳钢与普低钢焊接时的( )取决于普低钢本身的焊接性能。

A．结合性

B．焊接性能

C．工艺性

D．延伸性