"Be careful " Tom(shouted) a laughed b called c smiled d fou

Be careful to make sure you can be there on time.注意按点到达那里.
Be careful not to fall into the water when you are on boat.划船时小心别掉水里.

e careful 是固定搭配“ 当心,小心”
careful 是形容词,前用be 构成：系表结构

从意义上来说差不多,但是beware的程度比be careful要严重一些.
像接触危险物品,涉及到人身安全之类的一般是用beware.
像过马路,做出慎重决定,情感方面的一般用be careful.
而且be careful的小心多带有“仔细谨慎”的意思.beware更适用于警告.
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贴一些例句给你看：
1. He is extremely careful about his appearance.
他十分讲究外表.

2. He is careful in his speech.
他说话谨慎.

3. After careful consideration, we've decided to accept their offer.
经过慎重的考虑,我们决定接受他们的提议.

4. Be careful crossing the road.
过马路要当心.

5. You should be more careful with your money.
你花钱要慎重一些.

6. Be careful not to/that you don't hurt her feelings.
当心别伤了她的感情.

7. Be careful of the dog; it sometimes bites people.
留心那条狗, 有时候咬人.

8. Be careful (about/of) what you say to him.
对他说话可得小心.
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1. Beware of what you do with this dangerous substance.
你处理这些危险品时,可要当心.

2. Beware wet paint!
注意--油漆未乾!

3. He told us to beware (of pickpockets, the dog, icy roads).
他告诉我们要当心（小偷、狗、结冰的道路）.

4. I was told to beware lest I injure him.
有人关照我,要我小心别伤害他.

5. Beware your hat, lest it should be blown away.
当心你的帽子别被吹走.

Be careful较书面化.覆盖面较广,可指工作,人身安全等.
look out口语化,多指人身安全.

你说的是句子吧?Be careful是祁使句,所以要用动词原型,如：let's go./Enjoy yourself!这些句子句首都应该用动词原型

1.be careful 小心点,让对方多加留意,谨慎小心
be careful with.../ be careful not to do sth
2.be carefully 不是固定搭配,后面还应该接动词的过去分词,表示"被小心/仔细地..."
如:This task should be carefully finished.
3.take care 保重/小心,留神,注意,一般单用
4.look/watch out (for...) 小心/留神/注意...
如:Please look/watch out for this dog.

about

Be careful!The car is coming!
When you do your homework,you must be careful.
It is careful of you to remove the peel of the banana.
They are careful about how to deal with the matter.

小心的意思.朋友,好好努力学习吧,我相信你是最棒的!

e careful of …
注意,小心.接名词,动名词或从句.
Please be careful of your spelling.
Be careful of what they have said.
be careful with…
小心……
[句型解析]
嘱咐别人小心做事,我们用上Be careful with...with接名词或动名词也说Be careful (not) to do...或Be careful that you don’t...
[实例]
1.Be careful with the wet paint.
小心,油漆未干
2.Be careful that you don’t catch a cold.Put on more clothes before you go out.
小心别感冒了出门之前多穿点衣服
3.Be careful not to spill the milk.
小心别把牛奶溅出来了

e careful 提醒要小心,要保重,一般是预先的提醒或者表示关心.而look out是指你已经看到有事发生,比如车要撞过来了,情况紧急,你可以大喊look out!

Be careful about the fire!
Look out for the fire!

不对不对...
be careful是祈使句...不能去掉be...
be careful with the glass!的意思是小心杯子!
词组be careful with sth.就是小心sth.的意思...

小心

这个问题涉及两个语言点.
1.我想楼主指的Be careful .和Be quiet .应当是一个句子而不是固定搭配吧.那就涉及到祈使句了.祈使句是一个没有主语的,用作祈求与命令的句子.而它的祈使动词必须是动词原型.Eg:Shut the door!Open the window!
2.is am are 的原型是什么呢?对!就是此处的Be!
To include,此处必须是用Be 而不是is!（北在南方原创）
最后祝楼主英文能够更上一层楼!

前者是表“小心翼翼(或仔细的）去做某事”,如：He was careful to answer the questions which were asked by the reporter.他小心翼翼地回答了记者提出的问题.
后者是表“小心别.、避免去干...”,如：he was very careful not to make his parents angry.他非常小心避免父母生气.

carefulluy 这个单词打错了吧,只有carefully,carefully是副词只能修饰动词,be carefully的说法不对,As long as you drive carefully,you will be very safe.
如果你开车小心,你就会很安全.这里carefully是修饰drive的.而be careful =carefully,careful是形容词,be是系动词,也可以单独使用,是小心的意思例如 Be careful crossing the road.
过马路要当心.