past passed

　　past ：gone by or history 經(jīng)過，過去、以往。

　　例：The car drove past my house.

　　My past is very interesting.

　　passed：pass的過去時態(tài)。

　　例：We passed through the town without stopping.

　　principal principle

　　principal：the head of a school 校長

　　例：The principal spoke to us today.

　　principle：a principle is an important fact or law.

　　例：The principle of democracy is important to ourcountry.