Why not try another way _______ you may do your experiment better and more quickly?
| A．/ | B．which | C．of which | D．by which |
This also keeps the air，soil，water crops________ chemicals.
| A．out of | B．out from | C．free of | D．rid of |
____polite to others and you can get friendship in turn.
| A．Be | B．To be | C．Being | D．/ |
There are many tall old trees____ in and around our school.
| A．stood | B．to stand | C．standing | D．being standing |
A quarrel _________, which made him ______ his family.
| A．was broken out; break away |
| B．broke out; break away from |
| C．was broken away; break down |
| D．broke down; break out |
Though he was _______,he looked down upon those who had a lot of money.
| A．well off | B．rich | C．badly off | D．well-known |