The scientists recommend that studies ________ to find out what side effects the medicine might cause.
| A．be done | B．should do |
| C．will be done | D．are done |
They were trying to remove harmful ___________ from cigarettes.
| A．content | B．substances | C．materials | D．mixtures |
Jack was sure to get this year’s scholarship as the standards of scholarship were not terribly_________
| A．tough | B．rough | C．difficult | D．demanding |
I can’t put up with the _____atmosphere here.
| A．silent | B．aimless | C．lifeless | D．deadly |
The government will __________ the country through the difficulties ahead.
| A．direct | B．lead | C．guide | D．draw |
I always persuade Mary to have both feet on the____as she wants to marry a millionaire and accomplish her goals in an easy way.
| A．ground | B．earth | C．location | D．place |