rise in carbon dioxide is causing steady increase in global warming.
| A．The; a | B．不填; a | C．The; 不填 | D．A；the |
QQ,________you can chat with your friends, makes communication easy.
| A．why | B．which | C．that | D．where |
_____ you don’t lose heart, I’m sure you can pass the coming examination.
| A．Unless | B．As long as | C．If not | D．Although |
__________all kinds of difficulties，the workers have made rapid progress in the construction of
the World Expo 2010 Shanghai．
| A．With | B．For | C．Under | D．Beyond |
_______of the household rubbish___recycled or reused since the new technology was applied.
| A．Three-fourth; has | B．Three-fourths; have |
| C．Three-fourths; has been | D．Three-fourth; have been |
Health problems are closely connected with bad eating habits and a____ of exercise.
| A．limit | B．lack | C．need | D．demand |