since 和 from 表示时间的用法区别:
一、《薄冰英语惯用法词典》指出:
since 是指延续到说话时刻的动作或情况开始于何时,是站在动作终止的时间点上往过去追溯计算。而 from 只表示某事的起点。
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I was there from three o'clock, but nobody came. 我从3点起一直在那儿,但谁也没来过。
不可说:I was there since three o'clock, but nobody came.
I've been here since three o'clock, but nobody's come yet; I think I'll go home soon. 我从3点起就一直在这儿,但是没有人来过。我想这就回家去。
不可说:I've been here from three o'clock, but nobody's come yet; I think I'll go home soon.
有 from 表示时间起点的句子,现在、过去、将来的时态都可以用;而 since 表示时间起点的句子不用将来时态。
二、since 可以作介词,也可以作连词(引导时间状语从句),from 只能作介词,不能作连词。例如:
She has missed it since we moved to the city. 自从我们搬进城后她一直想念它。(《张道真高级英语词典》p.1435)
不能说:She has missed it from we moved to the city.