To understand the grammar of the sentence，you must break it______ into parts．
| A．down | B．up | C．off | D．out |
The driver can adjust the heating in winter and the air conditioning in summer to suit his own _____.
| A．leisure | B．preference | C．convenience | D．selection |
She felt _____ of having asked such a silly question when the audience couldn't help laughing.
| A．guilty | B．crazy | C．miserable | D．ashamed |
After a short holiday, he _____ himself once more to his studies.
| A．applied | B．converted | C．engaged | D．exerted |
Although he hasn't any formal qualifications, Betas _____ to do well for himself.
| A．managed | B．succeeded | C．arranged | D．convinced |
John always tries to _____ people who are useful to him professionally.
| A．develop | B．provoke | C．correspond | D．cultivate |