Can you explain ____ most deserts are located near the west coast of the continents?
| A．why is it that | B．why it is that |
| C．how it is that | D．how is it that |
Parents must take good care of their children, _____ they?
| A．mustn’t | B．don’t | C．needn’t | D．aren’t |
He must be in the reading-room, _____ he?
| A．mustn’t | B．doesn’t | C．needn’t | D．isn’t |
It was 4:25 a.m. _____ the ambulance arrived to take the body of Miss Lee.
| A．when | B．until | C．that | D．since |
It was years _____ I had visited my hometown in Dalian, Liaoning Province.
| A．after | B．that | C．since | D．when |
Not until _____ his shoes did he enter one of the rooms of the Japanese house.
| A．he removes | B．did he remove |
| C．he had removed | D．had he removed |