When he took a gun out everyone backd away nervously.
He agreed to help but backed out when he found how difficult it was.
back somebody up从道义上或行动上支持：
The headmaster never backed up his staff.（backed them up）If a parent complained about a teacher he assumed that the teacher was in the wrong.
I'm for doing nothing till the police arrive.／I'm against doing anything till the police arrive.
—I want to see Mrs Pitt.Is she in？
—No，I'm afraid she's out at the moment.／No，I'm afraid she's awayfor the weekend.
—When will she be back？
—She'll be back in half an hour/next week.
be in for（tr）将要遇上（常跟某种令人不愉快的事）：
Did you listen to the weather forecast？ I'm afraid we're in for a bumpy flight.
If you think that the work is going to be easy you're in for a shock.
The storm is over now；we can go on.
Don't expect her to answer the doorbell at eight o'clock on Sunday morning.She won't be up.
be up to（tr）体力或智力足以……（宾语常用it，但也可用动名词）：
After his illness the Minister continued in office though he was no longerup to the work/up to doing the work.
be up to something／some mischief／some trick／no good 从事或忙于某种调皮的、不正道的或有害的事／捣鬼：
Don't trust him；he is up to something／some trick.
The boys are very quiet.I wonder what they are up to.
it is up to someone（常带动词不定式）此事是某人的职责：
It is up to the government to take action on violence.
I have helped you as much as I can. Now it is up to you.
This report bears out my theory.（bears my theory out／bears it out）
The news of her death was a great shock to him but he bore up bravely and none of us realized how much he felt it.
The wind blew out the candle.（blew the candle out／blew it out）
They blew up the bridges so that the enemy couldn't follow them.（blew the bridges up／blew them up）
Just as we got to the bridge it blew up.
The children blew up their balloons and threw them into the air.（ blew the balloons up／blew them up）
I put the kettle on the gas ring and then went away and forgot about it.
When I returned， the water had all boiled away and the flame had burnt a hole in the kettle.
The milk boiled over and there was a horrible smell of burning.
break down a door etc.用强力敲破或撞破：
The firemen had to break down the door to get into the burning house.
（break the door down/break it down）
break down figures 将一数目分别列在不同项目下以作进一步说明：
You say that 10,000 people use this library.Could you break that down into age-groups？
He broke down when telling me about his son's tragic death.
At first he refused to admit his guilt but when he was shown the evidencehe broke down and confessed.
After years of overwork his health broke down and he had to retire.
The car broke down when we were driving through the desert and it tookus two days to repair it.
The negotiations broke down because neither side would compromise.
break in（intr），break into（tr）
Thieves broke in and stole the silver.
The house was broken into when the owner was on holiday.
I was telling them about my travels when he broke in with a story of hisown.
break in ?a young horse／pony etc.（tr）训练（马等）以供驾驭使用：
You cannot ride or drive a horse safely before he has been broken in.
He took a bar of chocolate and broke off a bit.（broke a bit off/broke itoff）
A piece of rock broke off and fell into the pool at the foot of the cliff.
Ann has broken off her engagement to Tom.（broken her engagement off/broken it off）
They were in the middle of an argument but broke off when someone came into the room.
War broke out on 4 Angust.
They locked him up in a room but he broke out.
The police are looking for two men who broke out of prison last night.
If that ship stays there she will break up／she will be broken up by the waves.
The old ship was towed away to be broken up and sold as scrap.
Divorce breaks up a lot of families.（breaks families up／breaks them up）
The school broke up on 30 July and all the boys went home for the holidays.
The meeting broke up in confusion.
bring someone round（tr；宾语常位于 round 之前）
After a lot of argument I brought him round to my point of view.
She fainted with the pain but a little brandy soon brought her round.
bring a person or thing round（tr；宾语常位于 round 之前）把人或物带到某人的住所去：
I have finished that book that you lent me；I'll bring it round（to your house）tonight.
She brought up her children to be truthful.（brought her children up／brought them up）
At the last committee meeting，the treasurer brought up the question of raising the annual subscription.（brought the question up／brought it up）
The mob burnt down the embassy.（burnt the embassy down／burnt it down）
The hotel burnt down before help came.