A new ______bus service to Tianjin Airport started to operate two months ago .
| A．regular | B．physical | C．usual | D．former |
His parents were so poor that they couldn’t _______ to buy a computer for their only son .
| A．pay | B．cost | C．spend | D．afford |
Who did the teacher , as well as the monitor , _______ an article for the wall newspaper?
| A．has write | B．has written | C．have write | D．have written |
The question _______ we can get enough coal for the winter has not been cleared up yet .
| A．that | B．if | C．which | D．whether |
Every possible means ________ to prevent the air pollution , but the sky is still not clear.
| A．is used | B．are used | C．has been used | D．have been used |
Some people thought ________ possible to live on out space in the future .
| A．it | B．it be | C．it is | D．that is |