once begin decide ride 这几个英语单词的语法知识请告诉我，我们要讲解这些单词

once = one time 一次 I did it just once.
previously (done): Once memorized, it's hard to forget.
at once = 立即；马上
http://dict.cn/search/?q=once
begin = commence = start = get to = take off = get off to
http://dict.cn/search/?q=begin
decide = resolve = make a decision/resolution = decide on something
http://dict.cn/search/?q=decide
ride = drive :give sb a ride = drive in sb's vehicle; 比喻 have a good time
http://dict.cn/search/?q=ride

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