Extra—outside;Intra—within
Why don’t you join an extracurricular activity,such as a club,the sc自序 a team?
你为何不加入一种课外活动呢？例如社团，校刊或是球队。
You said you would stick to the topic,but you keep introducing extraneous issues.
你说你将不离主题，可是却一直介绍不相干的事物。
Reliable salesmen do not make extravagant claims for their product.
可靠的推销员不过夸张他们的产品。
In a few months,the extravagant heir spent the fortune of a lifetime.
几个月内那个挥霍无度的继承人花掉了一生的财富。
The intramural program,in which one class competes with another,gives you a greater chance to participate than the interscholastic program between teams of competing schools.
校内班际间的比赛，比校际间的比赛更能提供你参与的机会。
The Democrats are trying to heal intraparty strife so as to present a united front in the coming election.
民主党员设法和解党内的纷争，以求在未来的选举中呈现出统一的阵线。
Commerce between the states is regulated by the Interstate Commerce Commission,but intrastate commerce is supervised by the states themselves.
州际间的贸易由州际贸易委员会调节，而各州内部的贸易则由各州督导。
Patients are nourished by intravenous feeding when too ill to take food by mouth.
当病人不能由口进食时，需靠静脉注射给食来提供养分。