There are still many problemsbefore we are ready for a long stay on the Moon.
| A． | solving | B． | solved |
| C． | being solved | D． | to be solved |
I waited for him at the train station for an hour and I was afraid that he may miss the train, but luckily, he showed up with only ten minutes．
| A．remain | B．to remain |
| C．remained | D．remaining |
The drama, “The Empress of China" that was pulled off the air for technical reasonsnow back on TV．
| A．is | B．are | C．has | D．have |
Taught in a more professional way, youthe swimming skill much better．
| A．might master | B．would have mastered |
| C．can have mastered | D．could master |
Following the decline in house prices in many small and medium-sized cities, there are now signshome prices in majors cities may also be set for a slide．
| A．which | B．that | C．how | D．what |
— Can I lie about seeing a text message because I was too busy or lazy to respond to it ?
—Receiving a text message does not necessarily mean you have to respond． Why waste a perfectly good liethe truth will serve?
| A．unless | B．until | C．when | D．while |