Since the Obama administration took office, the China—US relations ________ positive development thanks to joint efforts of both sides, President Hu said at the Nuclear Security Summit in Washington, April,12,2010.
| A．witnessed | B．were witnessed | C．had witnessed | D．have witnessed |
—Have you finished the work?
—Not yet. I _______ to do it just a moment ago.
| A．set off | B．set up | C．set out | D．set down |
______ is known to everybody, the moon travels round the earth every month.
| A．It | B．That | C．As | D．Why |
When you are driving on this road, you have to limit your speed _____ 60 miles per hour.
| A．in | B．at | C．to | D．below |
—What do you mean. There are only ten tickets?
—There ______ be twelve.
| A．should | B．would | C．will | D．shall |
Jane is said _______ an opera singer in her youth.
| A．being | B．to be | C．to have been | D．having been |