The machine needs a complete______since it has be

It is doubtful______the work can be completed on time.A．ifB．whyC．thatD．when

I dont think it advisable mat Tim ______ assigned to the job since he has no experience.A．

either you or I ________able to design the machine. A. is B. has been C. are to be D. a

The house ______in bad repair since he moved out.A、wasB、has beenC、had beenD、was being

In______, Chinatown has been the center of its Chinese community since the 1850s, which is

Speaker A: The experiment has been completed, hasnt it？ Speaker B: ______A．Yes. We need an