The island where these rare birds nest has been declared a _____.
| A．observation | B．reservation | C．preservation | D．conservation |
You are working too hard. You'd better keep a ________ between work and relaxation.
| A．promise | B．lead | C．balance | D．diary |
Cynthia is not ashamed of what she does,she ends up doing something wrong.
| A．in case | B．even though | C．as though | D．now that |
It’s standard practice for a company like this one______ a security officer.
| A．employed | B．being employed | C．to employ | D．employs |
Sometimes, ________ we show our gratitude for a person is reflected in the kind of food we serve him or her.
| A．when | B．whether | C．why | D．how |
________they decide which college to go to，students should research the admission procedures.
| A．As | B．While | C．Until | D．Once |