The project tumed out to be very good,       _ was more than we could expect.      [ ]

A. what                          

B. that      

C. which                          

D. this

高压蒸汽采暖系统管道中热媒的最大允许流速应符合的规定为( )。

A．汽水同向流动时60m/s，汽水逆向流动时80m/s
B．汽水同向流动时80m/s，汽水逆向流动时60m/s
C．汽水同向流动时50m/s，汽水逆向流动时70m/s
D．汽水同向流动时70m/s，汽水逆向流动时50m/s