Tra từ as - Từ điển Oxford Advanced Learner 8th

as preposition, adverb, conjunction BrE [əz] NAmE [əz] BrE strong form [æz] AmE strong form [æz]
preposition
1. used to describe sb/sth appearing to be sb/sth else
• They were all dressed as clowns.
• The bomb was disguised as a package.
2. used to describe the fact that sb/sth has a particular job or function
• She works as a courier.
• Treat me as a friend.
•I respect him as a doctor.
•You can use that glass as a vase.
•The news came as a shock.
•She had been there often as a child (= when she was a child).

Word Origin:
Middle English: reduced form of Old English alswā ‘similarly’ (see ↑also).
Idioms: ↑as against something ▪ ↑as and when ▪ ↑as for somebody ▪ as from … of … ▪ ↑as if though ▪ ↑as it is ▪ ↑as it were ▪ ↑as regards something ▪ ↑as to something ▪ ↑as you do

adverb
1. as… as… used when you are comparing two people or things, or two situations
• You're as tall as your father.
• He was as white as a sheet.
•She doesn't play as well as her sister.
•I haven't known him as long as you (= as you have known him).
•He doesn't earn as much as me.
•He doesn't earn as much as I do.
•It's not as hard as I thought.
•Run as fast as you can.
•We'd like it as soon as possible.
2. used to say that sth happens in the same way
• As always, he said little.
• The ‘h’ in honest is silent, as in ‘hour’.

Word Origin:
Middle English: reduced form of Old English alswā ‘similarly’ (see ↑also).

Which Word?:
as / like
You can use both as and like to say that things are similar.
Like is a preposition and is used before nouns and pronouns: ▪ He has blue eyes like me.
As is a conjunction and an adverb and is used before a clause, another adverb or a clause beginning with a preposition: ▪ She enjoys all kinds of music, as I do. ◇ ▪ Repeat these five steps, as in the last exercise.
In informal English like is frequently used as a conjunction or an adverb instead of as: ▪ Nobody understands him like I do. ◇ ▪ I don’t want to upset him again like before. It is also used instead of as if: ▪ It looks like we’re going to be late. These uses of like are common but are not considered correct in formal written English.
You will find more help on the use of as and like in the entries for particular verbs, such as act, behave, etc.

conjunction
1. while sth else is happening
• He sat watching her as she got ready.
• As she grew older she gained in confidence.
2. in the way in which
• They did as I had asked.
• Leave the papers as they are.
•She lost it, just as I said she would.
3. used to state the reason for sth
• As you were out, I left a message.
• She may need some help as she's new.
4. used to make a comment or to add information about what you have just said
•As you know, Julia is leaving soon.
•She's very tall, as is her mother.
5. used to say that in spite of sth being true, what follows is also true
Syn: ↑though
•Happy as they were, there was something missing.
•Try as he might (= however hard he tried), he couldn't open the door.
more at as well at ↑well, as yet at ↑yet

Word Origin:
[as] Middle English: reduced form of Old English alswā ‘similarly’ (see ↑also).

Language Bank:
process
Describing a process
▪ This diagram illustrates the process of ▪ paper-making. / This diagram shows how ▪ paper is made.
First ▪ / First of all ▪, logs are delivered to a paper mill, where the bark is removed and the wood is cut into small chips.
Next ▪ / Second ▪, the wood chips are pulped, either using chemicals or in a pulping machine.
▪ Pulping breaks down the internal structure of the wood and enables ▪ / allows ▪ the natural oils to ▪ be removed.
Once ▪ / After ▪ the wood has been pulped, the pulp is bleached in order to ▪ remove impurities. /…is bleached so that ▪ impurities can ▪ be removed.
The next stage is to ▪ feed the pulp into the paper machine, where it is mixed with water and then ▪ poured onto a wire conveyor belt.
As ▪ the pulp travels along the conveyor belt, the water drains away. This causes ▪ the solid material to ▪ sink to the bottom, forming a layer of paper.
At this point ▪ the new paper is still wet, so ▪ it is passed between large heated rollers, which press out the remaining water and simultaneously ▪ dry the paper. / …dry the paper at the same time ▪.
The final stage is to ▪ wind the paper onto large rolls. / Finally ▪, the paper is wound onto large rolls.
notes at ↑firstly, ↑lastly
Language Banks at ↑conclusion, ↑first

Which Word?:
as / like
You can use both as and like to say that things are similar.
Like is a preposition and is used before nouns and pronouns: ▪ He has blue eyes like me.
As is a conjunction and an adverb and is used before a clause, another adverb or a clause beginning with a preposition: ▪ She enjoys all kinds of music, as I do. ◇ ▪ Repeat these five steps, as in the last exercise.
In informal English like is frequently used as a conjunction or an adverb instead of as: ▪ Nobody understands him like I do. ◇ ▪ I don’t want to upset him again like before. It is also used instead of as if: ▪ It looks like we’re going to be late. These uses of like are common but are not considered correct in formal written English.
You will find more help on the use of as and like in the entries for particular verbs, such as act, behave, etc.