He made a mistake, but then he corrected the situation _______ it got worse.
| A．until | B．when |
| C．before | D．as |
I found it quite necessary ______ a foreign language.
| A．learing | B．to learn | C．learn | D．to learning |
______ in Shanghai for more than ten years, he know the city very well.
| A．Living | B．Having lived | C．Lived | D．Having been lived |
Study hard , ______ you will not pass the exam .
| A．and | B．otherwise | C．if | D．unless |
I hate going out alone，so I often ask my friend to ________me.
| A．defend | B．protect | C．accompany | D．guard |
Harry Potter is such an interesting book _______all kids like to read.
| A．as | B．that | C．/ | D．which |