28. You can’t complain of being lonely____you don’t make any effort to communicate with others.
| A．when | B．until | C．unless | D．Once |
Come and see me whenever ____.
| A．you are convenient |
| B．you will be convenient |
| C．it is convenient for you |
| D．it will be convenient for you |
As we can see, the prices of vegetables _____ according to the season.
| A．vary | B．fall | C．rise | D．reject |
I felt very tired when I got home. and I _______ straight to bed.
| A．go | B．went |
| C．had gone | D．have gone |
Once the new rules are made，what matters much next is how they will be________to all the members of the club.
| A．devoted | B．referred |
| C．applied | D．directed |
Nowadays people are more concerned about the environment _______ they live.
| A．what | B．which |
| C．when | D．where |