It's quite obvious that the aging population in China will cause heavy pressure on ________ whole society in the future．
| A．／；the | B．the；／ | C．a；the | D．a：a |
The work he devoted his time to _____ worth praising.
| A．was | B．be |
| C．being | D．been |
On Sundays there were a lot of children playing in the park, _______ parents sat together joking.
| A．their | B．whose |
| C．which | D．that |
I’ll come after the meeting if time ______.
| A．permits | B．is permitting |
| C．is permitted | D．has permitted |
Nothing that he suggested _____ to be of any use.
| A．prove | B．proved | C．proving | D．to prove |
The visitor asked to have his picture taken _______ stood the famous tower.
| A．that | B．at which |
| C．when | D．where |