before是什么意思
before的用法？
这里的before可以是介词，后面接了动名词putting；也可以认为是连词，后面是时间状语从句的省略。如果当成是连词，后面的句子出现省略了，补全句子应该是：before she puts on a blank expression and not gives them any visual social feedback。原句结构分析：In it 介词短语作状语a mother名词作主语 is asked谓语，一般现在时的被动语态 to interact主语补足语 with her child介词短语作状语 in a normal way介词短语作方式状语 before putting on a blank expression and not giving them any visual social feedback介词短语作时间状语 或者时间状语从句的省略。句子的翻译：在实验中，一位母亲被要求以正常的方式与她的孩子互动，然后面无表情，不给他们任何视觉社会反馈。before /bɪˈfɔː(r)/ 的用法： 1. prep. 在……之前，先于；在……面前。举例：She hesitated before replying. 她犹豫了一下才回答。Before going shopping, I made a shopping list. 去购物之前，我列了一张购物清单。She waited a full week before saying no. 她等了整整一个星期才说不。He thinks little before doing. 他做事很少考虑。2. conj. 在……以前；到……为止；以免，不然；（宁可……而）不愿。后面通常接句子举例：I cleared my desk before I left. =I cleared my desk before leaving.离开前我清理干净了办公桌。I could drive a car before I left school. =I could drive a car before leaving school我在中学毕业前就会开车了。He took a deep breath before he went under. =He took a deep breath before going under. 他在钻下水前深深地吸了口气。Some children can read and write before they go to school. =Some children can read and write before going to school. 有些孩子在上学前就会看书写字了。注意：before的这俩种用法是可以互相转换的。前提是主句的主语和从句的主语一致。也就是状语从句的省略现象。
before是什么意思
before意思是在…以前。读音：英[bɪˈfɔː(r)]，美[bɪˈfɔːr]。释义：（1）prep. 在…以前；在…面前；在前面。 （2）conj. 在…以前；到…为止；到…之前；以免；不然。（3）adv. 以前；过去；已经。例句：Annie was born a few weeks before Christmas.安妮出生在圣诞节前几周。近义词1、formerly读音：英[ˈfɔːməli]，美[ˈfɔːrmərli]。释义：adv. 以前；从前。例句：He had formerly been in the Navy.他从前在海军服役。2、ago读音：英[əˈɡəʊ]，美[əˈɡoʊ]。释义：adv. （与动词简单过去时连用）以前。例句：He was killed a few days ago in a skiing accident.几天前他在一场滑雪事故中丧生。
