Recently the Ministry of Environmental Protection issued a circular saying that China may adopt flexible working hours and stop school classes_____the highest air pollution warnings.
| A．for fear of | B．in terms of | C．on top of | D．in case of |
An idea came to him ___ he might do the experiment in another way.
| A．which | B．when | C．what | D．that |
It is so wet there that the trees are extremely tall, some ________ over 90 metres.
| A．are measured | B．measuring | C．measured | D．measure |
Rather than ___ on a crowded bus, Tom always prefers __ a bicycle.
| A．ride; ride | B．riding; ride | C．ride; to ride | D．to ride; riding |
Perseverance is a kind of quality --- and that’s ________ it takes to do anything well.
| A．why | B．that | C．which | D．what |
A heavy learning burden leads to unhealthy behaviors such as poor eating habits, which ___ damage the health of students.
| A．in its turn | B．in return | C．in turn | D．by turns |