How long did it take them to get ___ this river?
A.through B,over C.across D.till
____ has helped to protect the environment is worth praising.
| A．Who | B．The one | C．Anyone | D．Whoever |
—Why didn’t Tom go to the concert last night ? — I have no idea, but I think he _____ in his study.
| A．read | B．have read |
| C．was reading | D．would read |
Being examined twice a year is the rule that every driver _____ obey in this city.
| A．shall | B．can | C．ought to | D．need |
I’m calling to ask for information about the position____ in the local TV news.
| A．advertising | B．advertised |
| C．having advertised | D．to advertise |
It has been proved ____ several new kinds of medicine____ a positive effect on the cure of H7N9.
| A．which，has | B．if, has |
| C．that, have | D．what, have |