There are many trees and flowers on_____s

其实可以至少有三种方法来表达”河流、街道两边种树、花草等“,例如,我们来翻译”在街道两边长满了花草“这句话：There are trees and grass on both sides of the street（both表示两边都有,side用复数）There are trees and grass on each side of the street.（each表示每侧都有,side用单数,但是不能用every,因为every表示三者或者三者以上）There are trees and grass on either side of the street（either表示两侧任何一侧都有,side用单数）.希望你能理解,如果还有疑问,请追问.