at:表达一个特定的地方或一个事件发生的时间 I go to sleep at nine o'clock.
to:朝向某一个位置 I walk to the store.
in:内 Put the apples in the box.
on:上 Put the book on the table.
as:用来比较 The rat is as big as a dog.
of:表现部分与整体之间的关系 I eat two slices of pizza.
for:用於指示的对象,目标,或者一个动作或活动的目的 I work hard for money.