Professor Jordon is well known for his __________ into the habits of the common housefly.
| A．examination | B．introduction |
| C．research | D．expression |
Fujian has shut down the chicken markets ______ human infections of H7N9 were found.
| A．whose | B．why | C．which | D．where |
I got to the lecture hall very early, ______ to get a good rest.
| A．hoping | B．hoped | C．to hope | D．hope |
It hasn’t been announced ______ the plane is to take off.
| A．where | B．when | C．how | D．why |
Students ______ to do some voluntary work every year.
| A．were encouraged | B．are encouraged |
| C．encourage | D．encouraged |
You can smoke here ______ you leave a window open to let the smoke out.
| A．even though | B．so that | C．as long as | D．in case |