hit the nail on the head-往头上钉钉子？

hit 击打  heat 加热

hit it 

hit the car

to hit the nail on the head

完全正确

When you said that my car needed a new battery, you hit the nail on the head.

你说我的车需要换新电池，是完全正确的

hit the books

看书，努力学习

If I don't hit the books this week, I won't pass next week's exam

这礼拜不学习啊，下礼拜考试就过不了了。