from

在使用这两类介词短语时,要注意以下三点:

A. from 2 o'clock (today) 可与不同的动词时态连用, 而 since 2 o'clock 一般只与现在完成时或现在完成进行时连用:

1. I'm on holiday from 30 June. 我从6月30日开始休假。

2. I wrote the letter from two o'clock... 我从两点钟起写信……

3. I shall be with you in New York one week from today. 从今天起我将与你一起在纽约呆上一周。

4. I've changed my address since last year. 从去年起我就更换了地址。

B. from...可用于from...to(till/until)结构中：

1. The shop is open from 9:30 until 5:30. 这家商店从9点30分到5点30分营业。

2. The Museum is open from Monday to Friday. 博物馆星期一到星期五开馆。

C. since...着重强调“自从……起到目前动作或状态的持续情况”：

I have been doing it since the day before yesterday. 从前天开始我一直在干这个活儿。请做下面的英语试题： I haven't seen her ____ then on. A. from B. since C. after D. by

under his jacket 是个介词短语,作 from 的宾语,即介词短词作介词的宾语。这在英语里是很常见的。这种结构能把位置说得非常清楚,见 prepositional phrase as prepositional complement。

对学生讲, since 短语和 since 从句与现在完成时连用, 而 from 短语不与现在完成时连用, 是可以的。例如, 《新概念英语》(第二册) 便有这方面的试题(答案为 B): Tim has been in Australia for six months. His brother hasn't seen him ____ January. A. for B. since C. from D. by

但是,英语教师则应当注意到 from 的另一种用法:from 短语与现在完成时连用,表示“从过去某时一直延续至今的动作或状态”,尤其是 from a boy, from his childhood, from an infant, from olden times 等短语:

1. They have been friends from a child. 他们从孩子时起就是朋友了。

2. She has slept eight hours from yesterday morning. 她从昨天早晨起已经睡了8个小时了。

3. I would hesitate to say that the situation has improved from last year. (AP report, 1981) 我可不愿意说从去年起情况已有了改善。

新版的PEU明确指出，from有时候也可以与现在完成时连用，尤其是在from短语含有“从一开始就……”的意思时：

She's been like that from her childhood. (或 ... since her childhood.) 她从童年时代起就是那样。

From the moment they were married, they've quarrelled. 他们从结婚的那一刻起就一直吵架。

From the dawn of civilization, people have made war. 从有人类文明以来，人们就进行战争。

[附注]此外, from ... on, 相当于 since, 亦可与现在完成时连用。此外, from ... to, from ... till 有时也与现在完成时或现在完成进行时连用:

1. The two of them have been friends from that day on (= since that day). 他们两个从那天起成了朋友。

2. We've been working from morning to night. (= without stopping) 我们从早到晚一直在工作。