A large number of trees are being cut down to make paper.里面的are being是什么意思,合在一起的?怎么用?说具体点,谢谢

a large number of 同义词 a large number of ;large number of等的用法 the number of、a number of、large number的区别 a large number of+可数/不可数? A large number of的反义词 there is a large number of children还是there are a large number of children正确 There is a large number of还是there are a large number of a great deal of和a large number of区别 a number of和large numbers of的区别 a number of和large numbers of的区别 a large number of 和 huge amounts of 的用法 a large number of与huge amounts of的区别 masses of 与a large number of区别 a large number a lot a large amount of a large number of得区别 the number of,a small number of,a number of.,a great number of,a large/small number of,区别和后面该接可数和不可数名词 A large amount of money和a large number of money这样用是不是都对? a large number of和a large amount of的区别