Waves are beautiful to 阅读理解,速度!

Waves are beautiful to 阅读理解,速度!
Waves are beautiful to look at, but they can destroy ships at sea, as well as houses and buildings near the shore. What causes waves? Most waves are caused by winds blowing over the surface of the water. The sun heats the earth, causing the air to rise and the winds to blow. The winds blow across the sea, pushing little waves into bigger and bigger ones.
if the wind is strong enough,the waves will be big enough.and if the winds blow longer,the waves will be larger.in a small river there eill never be big waves.but at sea the wind can build up great waves.
if the wind is blowing at ten kilometers an hour,most waves at sea will be about one meter high.if it is blowing at one hundred and
twenty kilometers an hour,most waves will be about twelve meters high.in 1933 the USN reported the largest wave in history.it rose to thirty-four meters high.
（）11.sometimes waves will（）
A.do some washing for people
B.make ships going at sea
C.do bad things at sea
D.help people to seim in the sea
（）12.waves are made by（）
A.the sun
B.the sea
C.the rain
D.the winds
（）13.the size of wave is decided by（）factors
A.two
B.three
C.four
D.five
（）14.if the wind is blowing at fifty kilometers an hour,most waves will be（）meters high
A.five
B.ten
C.fifteen
D.fifity
（）15.when the largest wave rose in 1933,the wind must be blowing at（）an hour
A.thirty-four kilometers
B.three hunderd and forty metres
C.three thousand hundred kilometers
D.three hundred and forty thousand metres