短语介词是相当于一个介词的词组,它不能单独作句子成分.如:in front of,at the back of,next to等.‘instead of ’就是短语介词.
介词短语是由“介词+宾语”或“短语介词+宾语”构成的,它可以单独充当句子成分.如:in the bag,near the door,in front of the house等.by bike就是介词短语.
介词短语充当宾语补足语.例如:
They must keep their hands behind their backs.他们必须把手放在他们的背后.by bike就是介词短语.
这么说吧,你把介词短语当一个名词看,别一个词一个词研究.
A big bear ran out from ( behind a tree).
"behind a tree "看成名词的时候,就不觉得那么矛盾了.你要做的是适应这个句型,以后信手拈来.