经心的英文：
careful; conscientious; mindful

参考例句：

In an unthinking moment
不经心的时候,不小心时

The state of being drowsy or inattentive;dullness.
困倦昏昏欲睡或不经心的状态；懒散

He was very attentive to the ammeter.
他十分经心在意地望着电流计。

He was very attentive to the ammeter
他十分经心在意地望着电流计。

Careless steering brought the wind by the lee.
不经心的驾驶使风吹到帆的下风面来了。

The tractor had been damaged by rough usage.
这辆拖拉机因使用不经心而损坏了.

Better to read little with thought than much with levity and quickness.
与其不经心多读,无宁少读而用心思考

In incidentals the play is careless, or perhaps one should write carefree
这出戏在附带事件上是不太经心的，或许是想写得无忧无虑。

careful是什么意思：
adj. 小心的，仔细的，周密的，谨慎的；节约的

Have you heard the CARE？
你听说过美国援外汇款合作组织吗？

not care a hoot
1.毫不在乎

Be careful of the instruments.
别损坏仪器。

conscientious是什么意思：
adj. 认真的，尽责的，本着良心的；小心谨慎的

conscientious work
本着良心做的工作

He is a conscientious judge.
他是一个正直的法官。

He is a conscientious objector.
他是一个因宗教信仰等理由拒绝服役的人。

mindful是什么意思：
adj. 记住的；留心的

Have a good mind
很想…

Would you mind repeating it? =Would you mind saying it again?
再说一次，你介意吗?

My mind was submerged in terror.
我的心已淹没在恐怖之中。