He transplanted the little tree to the garden it was the best time for it.
| A．where | B．when | C．what | D．that |
Our monitor, who by then ______ admission to Fudan University, decided to do some part-time jobs to gain more practical experience.
| A．gained | B．was gaining | C．has gained | D．had gained |
Taking physical exercise regularly is an effective way to avoid ______ with the flu.
| A．to infect | B．infecting | C．to be infected | D．being infected |
The entry point tissue in the very front of eye functions as the window ______ all light has to pass on its way.
| A．which | B．that | C．across which | D．through which |
Misunderstandings arising from lack of social communication, if not ______ properly, may lead to serious problems.
| A．handling | B．being handled | C．handled | D．to handle |
Worldwide markets get tighter and the pain only lasts longer ______ international cooperation is strengthened in no time.
| A．because | B．if | C．unless | D．when |