Plastic bags are provided for our convenience but they have also __________ the pollution of the environment.
| A．referred to |
| B．led to |
| C．reacted to |
| D．attended to |
How beautifully she sings! I have never heard＿＿＿.
| A．the better voice | B．a good voice | C．the best voice | D．a better voice |
I’d be＿＿＿, if you could give me an early reply.
| A．pleasant | B．grateful | C．satisfied | D．helpful |
-When are you leaving?
-My plane _____ at six.
| A．took off | B．is about to take off | C．takes off | D．will take off |
I need some red ink badly, but there’s _____ at hand.
| A．nothing | B．a little | C．none | D．not |
You can go out _____ you promise to be back before 11 o’clock.
| A．so that | B．as far as | C．so long as | D．in case |