He tried to invite some famous pop stars to sing in the concert ______, but failed.
| A．with free | B．for freely | C．with freedom | D．for free |
The hospital is ______ signs telling patients that it can offer only limited services.
| A．holding up | B．putting up | C．building up | D．going up |
You really need to go out and get some fresh air and sunshine. You ______ overworked during the last two weeks.
| A．have been | B．were | C．had been | D．would |
—How long do you think it will be ________ we win the football World Cup?
—Perhaps twenty years.
| A．when | B．since | C．that | D．before |
Silk from China found its way to India, the Middle East and Rome, _______ spices and glass, which was not known to China.
| A．in exchange for | B．in return | C．in change for | D．in need of |
Li Yang, the founder of Crazy English, says that he copies it down _______ he comes to a sentence.
| A．unless | B．while | C．because | D．every time |