攻关的英文：
attack a key problem

We must concentrate on key projects in agricultural science.
切实组织农业科学重点项目的攻关。

They had overcome one tough problem after another before working out this sort of energy-saving lamp
他们连连攻关终于研制成这种节能灯

He understands the way markets work and he is a troubleshooter and problem-solver in the Chinese system.
他理解市场运作的方式，在中国的体制内是一名攻关者和问题解决者。

attacking clear
比较平直的高远球

It was a planned attack.
这是一次有计划的袭击。

We will not attack unless we are attacked; if we are attacked; we will certainly counterattack.
人不犯我，我不犯人；人若犯我，我必犯人。

We have a key for the door of the house and a key for starting the car.
我们有房间门的钥匙和发动汽车的钥匙。

I left the key in the lock.
我把钥匙留在锁上，忘了取下来。

He fished in the bag for the keys.
他在袋子里摸找钥匙。

It was a complex problem.
这是一个复杂的问题。

Is the problem that easy?
问题有那么简单吗?

This is a prime problem.
这是一个有关质数的问题。