Because the circulating water is in a closed loop,_______is installed to cater for expansion and contraction of the water at different conditions of operation.

— I wonder ________ you’ll water this kind of flower .

50．—could you take care of our dog while we are away?—__________

It is a small country, yet has a lot of________ resources．

We drop a piece of metal into a jar full of water, the metal will float if it weighs less than______.

Water is the __46___ of all the things we eat and drink . Not many people understand this but __47____ quite true . The human body can go without ___48___ for a long time . We’ve got many examples for this . Yet two __49___ three days without water can usually make people __50____ . Man can’t live __51____ water .Many people don’t understand how ___52__ water the human body needs __53___ work well , and many people , especially young people , do not drink enough , ___54__ in very hot weather . Our body has mostly water , about 65% to 75% . That is to say about two thirds of our body is water . When we do sports , some of the water will get away from our body . __55 _ we don’t drink some water , we won’t have enough water． And if we don’t have enough water , we’ll feel tired and many of us will get ill . So you know how important water is to us .46.___________( )46.

Nearly________ of the surface of our planet is covered by water.

(单项选择)The black car drove away from them and  ____________

Putting in a new window will__________ cutting away part of the roof．

I just heard ______ bank where Dora works was robbed by ______ gunman wearing a mask.

_____ the importance of wearing seat belts while driving.

After the argument Colin ran away and__________since．