关键的英文：
crucial
key
pivotal

参考例句：

Ay, that's the substance of it.
啊！这是问题的关键！

The sixty-four-dollar question of the company is out of funds.
这家公司的关键问题是缺乏资金

Clothing is a key of success to businessmen, which is especially important in China.
着装是商人成功的关键，在中国尤其重要。

This was the hinge of fate of the whole campaign.
这是决定整场战役命运的关键点。

Such cost-saving measures could be crucial to future growth.
这样的成本降低，对于未来的成长十分关键。

Each tick of the clock was bringing the fatal hour nearer.
随着时钟的每一个滴答声，关键的时刻越来越近了。

The rocks of the Critical Zone can be grouped into two petrologic series
关键带的岩石可以分为两个岩组。

Foreign capital is mainly used in the key construction and in technology reformation of the existing enterprise.
外资主要用于关键的建设项目和现有企业的技术改造。

That was a critical factor in determining the technology adoption.
在决定技术的采用时，这是一个很关键的因素。

Comfort and versatility are key. These are not your traditional men’s suits.
舒适和多样性是关键。它们不是传统的男式西装。

crucial是什么意思：
adj. 至关重要的，关键性的；严酷的，艰难的

Salt is a crucial ingredient in cooking.
盐是烹调的一种重要材料。

The lack of clarity is especially crucial.
缺乏透明度是关键。

The foreign market was increasingly crucial.
国外市场越来越重要了。

key是什么意思：
n. 钥匙；线索；按键；调；关键
adj. 最重要的；关键的
v. 为…调音；用键盘输入

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。

pivotal是什么意思：
adj. 关键的；中枢的

Central or pivotal.
中枢的，中心的

Place a pivot pin into the pivot point.
把大头针扎在旋转点上。

So today is not only a pivot, but a confluence of pivots.
所以今天不仅是一个支点，还是一个支点的汇合。