一、careful的搭配与用法
1. 后接介词 of 或 about, 表示“当心”“留意”等。如：
Be careful of the traffic.
注意交通安全。
I think you should be careful about talking of the rebels as heroes...
我觉得你说话应该小心,不能把反叛分子当英雄。
It is important, I think, for everyone to be careful about claiming victory.
我想，每个人宣布胜利时都应该慎重。
Be careful about fire!小心火烛。
Be careful of the instruments.
注意别损坏仪器。
Be careful of the dog; it sometimes bites people. 当心那条狗，它有时候咬人。
You must be careful of [about] your pronunciation. 你要注意你的发音。
be careful 后一般不接介词 for。如：
我希望你要多注意身体。
正：I hope you’ll be more careful of [about] your health.
误：I hope you’ll be more careful for your health.
2. 表示做某事时要小心或仔细，其后通常接 in doing sth。如：
Be careful in crossing the street. 过马路时小心。
You cannot be too careful in driving a car. 开车时再怎么小心也不为过。
One cannot be too careful in guarding Party and state secrets.
保守党和国家的机密，慎之又慎。
如果后接名词，则通常用介词with。如：
Please be careful with my glasses (= Don't break them) .
请当心别打碎我的眼镜。
It would force industries to be more careful with natural resources.
这将迫使企业更加节约资源。
The waiter was being very careful with the soap so as not to spill it.
服务生拿汤的时候很小心，怕把汤泼出来。
Be very careful with this stuff, it can be dangerous if it isn't handled properly
这东西一定要小心，稍不注意的话就会有危险。
You will have to make a special effort to train your child to be careful with her pocket-money
你得格外注意培养孩子的节俭意识，零花钱要省着花。
I have to be more careful with the work tops, as wood marks easily.
我必须格外小心使用操作台，因为木头容易留下污迹。
Do be careful with that vase! 务必小心那个花瓶！
You have to be careful with people you don’t know. 对不认识的人得当心。
Be careful with money. 花钱精打细算；不乱花钱。
You should be more carful with your money.你应该更加不要乱花钱。
这个词接money时一般用with，常考考点。
3. 后接不定式，表示注意要做某事。如：
Be careful not to drop it. 小心不要把它掉了。
Be careful not to slip.
小心，别滑倒了。
She kissed me, careful not to smudge me with her fresh lipstick
她小心翼翼地吻了我，以免把刚刚抹上的口红弄到我脸上。
He was always careful to avoid embarrassment.
他总是小心谨慎地避免尴尬。
You must be careful to avoid being caught. 你必须小心，不要被抓住。
He was careful to keep out of sight.
他小心翼翼地躲开别人的视线。
Be careful not to wake the baby.
注意别吵醒了宝宝。
We had to be very careful not to be seen
我们得小心翼翼，不能被发现。
注意该用法与后接in doing sth的区别。比较：
He’s careful to read every sentence. 他注意读（即不漏读）每一个句子。
He’s careful in reading every sentence. 他读每个句子都很仔细。
4. 其后可接从句作宾语。如：
Be careful you don't bump your head.
留神别撞了头。
Be careful how you hold it. 小心拿好。
Do be careful (about) what you say. 说话一定要小心。
Be careful / Take care when you drive on icy roads.
在冰霜覆盖的道路上驾驶时要小心。
You can't be too careful when a young child is near water.
孩子在水边时，还是越小心越好。
后接 what 从句时，可用介词 of, about 等，但通常省略，但是若是接 that, how, when, where 等引导的从句，则一般不用介词；另外，从句谓语若指将来，通常要用一般现在时代替将来时。如：
Be careful that you don’t hurt her feelings. (=Be careful not to hurt her feelings). 当心别伤害她的感情。
以上是careful 作表语的一些用法；其实这个词也可以作定语：
He is the most careful driver she has ever met.
他是她见过的最谨慎的司机。
I'm sure you will appreciate that we must keep a careful eye on all our running costs
我们必须密切关注所有的运营成本，这一点我想您肯定会赞同。
You should give it careful reconsideration.
你应该仔细地重新考虑一下这个问题。
二careless 的搭配与用法
1. 表示某人做某事很粗心，通常用于it is careless of sb do sth。粗心，不小心
如：
It was careless of you to leave your camera in the taxi.
你把照相机留在计程车里实在太不小心了。
It was careless of me to leave the door open.
怪我粗心忘了关门。
Don't be so careless about/with spelling.
别那么粗心大意地犯拼写错误。
该句式也可换成以“人”作主语的句子。
如：
你犯这样的错误真是粗心。
It was careless of you to make such a mistake.
=You were careless to make such a mistake.
注意，这样用时句首的it为形式主语，不能改为 that。但是这类句子后面不出现不定式，那么句首的it也可换为 that。
如：
It was very careless of him.
=That’s very careless of him.
他太粗心了。
2. 比较be careless to do sth与be careless in doing sth：前者中的不定式为结果状语，指由于粗心而做了某事；后者中的in doing sth表示时间，其中的in相当于while，指在做某事时很粗心。
如：
He was careless to make the mistake.
他很粗心，结果出了错。
He was careless in typing the letter.
他打这封信时很粗心。
3. 表示“对……不在意或不关心”等，其后可接介词 about, of, with 等。
如：
He’s careless of [about] his speech.
他讲话随便。
She is careless of [with] his health.
她不注意身体。
Don't be careless of your own safety!
对个人安全可别马大哈！
She's careless about her hygiene
她不注意个人卫生。
He had shown himself careless of personal safety where the life of his colleagues might be at risk
当同事身处危险时他表现英勇，不顾个人安危。
He is careless with his pronunciation.
他对语音不注意。
Don’t be so careless with your money.
你花钱不要这样随便。
同样，可以作定语：
a careless worker/driver
粗心大意的工人 / 司机
a careless laugh/smile
淡然的一笑
She gave a careless shrug.
她漠然地耸了耸肩。
With a careless flip of his wrists, he sent the ball quickly on its way.
他手腕轻轻一抖，球就飞出去了。
Some mothers were a bit careless with money
有些当妈妈的花钱有点随意。
He's a rather careless fellow.
他这个人做事比较马虎。
A careless driver is a danger to the public.
粗心的驾驶员对于公众是一种危险。
One careless move loses the whole game.
一着不慎，全局皆输。
