帮忙作一篇高中语法填空The sea has always interested man.From it he can get food,minerals,and treasure.For thousands of years,he could sail on it._____(1)he could not go far beneath its surface.Man wants to explore deep into the sea.However

帮忙作一篇高中语法填空The sea has always interested man.From it he can get food,minerals,and treasure.For thousands of years,he could sail on it._____(1)he could not go far beneath its surface.Man wants to explore deep into the sea.However
帮忙作一篇高中语法填空
The sea has always interested man.From it he can get food,minerals,and treasure.For thousands of years,he could sail on it._____(1)he could not go far beneath its surface.
Man wants to explore deep into the sea.However,he must breathe air,he cannot stay under the water's surface for any ______(long)(2)of time.To explore the deep water,man faces even more dangers and problems.
A diver _____(3)wants to stay under water for more than a few minutes must breathe air _____(4)a special mixture of gases.He can wear a diving suit and have air _____(pump)(5)to him from above.Or he can carry a tank of air on his back and breathe through a hose and a mouthpiece.
Water weighs 800 times as much as air.____(push)(6)by tons of water,diver's bodies are under great pressure.
When a driver is under great pressure,his blood takes ____(7)some of the gases he breathes.As he rises to the surface ,the water pressure becomes _____(8),if the driver rises too quickly,the gases in his blood from bubbles.The diver is then suffering _____(9)the bends(潜水员病）.The bendscan cause a diver to double up in pain.They can____(10)kill him.
尤其是第2,5,7,9题最好解释一下为什么

帮忙作一篇高中语法填空The sea has always interested man.From it he can get food,minerals,and treasure.For thousands of years,he could sail on it._____(1)he could not go far beneath its surface.Man wants to explore deep into the sea.However
原文：The sea has always interested man.From it he can get food,minerals,and treasure.For thousands of years,he could sail on it.But he could not go far beneath（在……下方）its surface.
Man wants to explore deep into the sea.However,he is not a fish.Because he must breathe air,he can’t stay under the water’s surface for any length of time.To explore deep water,man faces even more dangers and problems.
A diver who wants to stay under water for more than a few minutes must breathe air or a special mixture of gases.He can wear a diving suit and have air pumped（打气）to him from above.He can carry a tank of air on its back and breathe through a hose（软管）and a mouthpiece （接口管）.
Water weighs 800 times as much as air.Tons of water pushes against a diver deep in the sea.His body is under great pressure.
When a diver is under great pressure,his blood takes in some of the gases he breathes.As he rises to surface,the water pressure becomes less.If the diver rises too quickly,the gases in his blood from bubbles（起泡）.The diver is then suffering from the bends（潜水员病）.The bends can cause a diver to double up in pain.They can even kill him.