Does the way you thought of___________ water clean make any sense?
Unless ________ , the murderer is likely to commit similar or further offences.
It is the first time that Chinese astronaut Wang Yue________as one of the volunteers for the Mars-500 test project .
---I bought three DVD copies of the film Avatar and now is left. Somebody just borrows something and never returns. ---Things like that happen all the time.
Among the most important questions the journalists wanted _____was how Greece could overcome economic crisis ?
It is most _____that the environmentalists will come to the area to investigate the possible damage caused by the serious pollution.