he decided to study abroad he decide to study abroad 为什么要加ed

he decided to study abroad
DECIDE 这个词,其实是个点动作.就是决定下的那一时刻,一般来说永远是过去的.
译过来：他决定了要去国外学习.
其实,你知道这句话的时候,他就在过去决定 好了.
如果对现在有影响,通常用完成时,如果没有,就用过去时.
一些此词用法：
decide [di'said]
vt.
裁决,判定,判决(竞争、争端)：
例句：The judge decided the case in favour of the defendant.
法官对此案做出有利于被告的判决.
解决(有争执或疑问的事情)：
例句：to decide an argument
解决一场争论
决定,决意；就…拿定主意；选定：
例句：I have decided to learn shorthand.
我已决意学习速记.
They've decided to buy the house in the country.
他们已拿定主意购买乡下的那座房子.
to decide which tie to wear
决定戴哪条领带
使(某人)下决心,使决定,使决断,使做出决断；对…起决定作用：
例句：The new evidence decided her.
新证据使她下了决心.
Jack's information decided the argument.
杰克的情报对争论的解决起了决定作用.
vi.
(在竞争、争端中)判决,判定,裁决(for,in favour of,against):
例句：The judge decided for (或in favour of) plaintiff.
法官做出了有利于原告的判决.
The court decided against the defendant.
法庭做出了不利于被告的判决.
决定,下决心,拿定主意,决心；选定,抉择：
例句：Finally we decided against buying a car.
最后我们决定不买汽车.
It was difficult to decide between the two.
两者难以抉择.