1 look afer it -------介词+代词
look it up --------代词+ 副词
2 一般来说,短的在前,长的在後面：
I met him quite by accident (1) on the bus to the library (2)the other day(3)
你也可以把the other day放到句首：
the other day(3) I met him quite by accident (1) on the bus to the library (2)
一般来说,在前或在後往往要看你的句子结构.在英语中,没有什麼句子的结构是一成不变的.