Only after he realized the significance of mastering two languages ______ English carefully.
| A．did he set about learning | B．did he set out learning |
| C．had he set about learning | D．had he set out learning |
Sandy could do nothing but _________ to his teacher that he was wrong.
| A．admit | B．admitted | C．admitting | D．to |
--The prison was ___________ fire last night.
--Someone must have set fire___________ it.
| A．on; with | B．on; to | C．over; with | D．should |
The __________ is just around the corner and you won't miss it.
| A．bicycle's shop | B．bicycle shop |
| C．bicycles shop | D．bicycles’ shop |
__________ she couldn't understand was__________ fewer and fewer students showed interest in her lessons.
| A．What; why | B．That; what | C．What; because | D．That; why |
Scientists say it may be five or ten years___________ it is possible to test this medicine on human patients.
| A．since | B．before | C．after | D．when |