behind的意思如下：
prep.在(或向)…的后面落后于在(或向)…的背面支持赞成是…产生（或发展）的原因成为（某人的）过去
adv.在(或向)…的后面在后面较远处留在原地拖欠积压(工作)
n.义同bottom，委婉说法，即屁股
当behind做名词，意为屁股时，同义词有buttocks nates arse butt backside bum buns can fundament hindquarters hind end keister posterior prat rear rear end rump stern seat tail tail end tooshie tush bottom derriere fanny ass
我来试着回答一下吧。
我个人认为这个单词behind的同义短语应该是：at the back of.（在…后面）。
例如：There is a blackboard behind the classroom.
＝There is a blackboard at the back of the classroom.
There is a desk behind me.＝There is a desk at the back of me.
希望我的回答能够尽快帮到你啊！
