---_______ one and a half months enough for the project to be finished?

　　---I am afraid not. The professor is ill and only after he recovers ________ go on with it.

A．Is; he can

B．Are; he can

C．Is; can he

D．Are; can he

直流水枪直流水枪是用以喷射密集水射流的消防水枪、包括无开关直流水枪、直流开关水枪和直流开花水枪等。