你的这个问题太大了。常用介词随便也有二三十个，如：at, in, on ,beside, by, near, behind, but, except , besides,among, between, from, to, with, without, about, like, into, onto, through,before,against, along, during, for, of, off, past, since, towards, until, within, up, down, per, over, upon,till 等等。
  
而常用介词短语，同样多不胜数。自己平时要善于积累。以in为例，可有：
in the morning(afternoon, evening。。。。。。。)
in the sun(rain,snow, wet, dusk。。。。。。)
in danger(peace, poverty, fashion, comfort, blossom。
  。。。。。)
in fear of(excitement,doubt,hope。。。。。。)
in October(summer, 2005。。。。。。)
in ancient times, in modern times, in the 19th century。
  。。。。。
in rags(ruins, knots,fun,joke。。。。。。)
in a hurry(circle,line, a queue。。。。。。)
in sight, in the army, in the wall, in this way。
  。。。。。
in English(price, length,ink。。。。。。)
in red(white。。。; short,brief。。。)
in case, in addition to, in two 
简直不胜枚举，就不一一举例了。