We can never expect ________ bluer sky unless we create________ less polluted world.
| A．a; a | B．a; the |
| C．the; a | D．the; the |
Don’t worry. I’m sure you’ll succeed _______ if you work hard.
| A．on time | B．in time | C．at times | D．ahead of time |
Many rules in English are ______, and large numbers of students feel ______ them.
| A．puzzled; puzzled with | B．puzzling; puzzled about |
| C．puzzled; puzzling with | D．puzzling; puzzling about |
He had to have the washing machine _________ last night.
| A．to mend | B．mending | C．mended | D．being mended |
You________ drink it, for it is poisonous.
| A．can’t | B．needn’t | C．may not | D．mustn’t |
They made a bet _____the white horse.
| A．for | B．with | C．on | D．in |