心正不怕雷打
A good conscience is a soft pillow.

心甘情愿
He did all this of his own accord.

心不在焉
You look absent-minded; what's wrong?

心满意足
The little boy sat there smiling, as happy as a clam.

心力交瘁
I don't know what to do. I just burned the candle at both ends.

心灰意冷
He was in black despair when he failed in the joint examination.(down in the bushes/in the dumps/lose heart) 

心有余悸
A burned child dreads the fires. (Once bitten, twice shy.)

心安理得
No matter what he said, I have the peace of mind. (have an easy conscience)

心血来潮
He did it just on the impulse of the moment.

心花怒放
My heart sings with joy because I receive over 300 letters a week from people around the world.  

小Car笔记：

dread：惧怕，恐惧 【常用词组】① in dread of someone：害怕某人 ② in dread of one's life：害怕有生命危险
impulse：冲动，心血来潮 【常用词组】① impulse buying：即兴购买，未经考虑仅凭一时冲动的购物行为  ② electrical impulse：电脉冲

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