1、definite

明确的;确定的

It's too soon to give a definite answer.

要给出一个明确的答复，现在还为时过早。

Her Royal Highness has definite views about most things.

女王陛下对大多数事情都有明确的观点。

(证据或信息)确凿的，确切的

We didn't have any definite proof.

我们没有任何确实的证据。

If you have any definite news of my husband, please let me know.

如果有我丈夫的确切消息，请一定告诉我。

清楚的;明显的;无疑的

There has already been a definite improvement.

已经有了显著的改进。

That's a very definite possibility.

那是很有可能的。

2、essential

绝对必要的;必不可少的;基本的

It was absolutely essential to separate crops from the areas that animals used as pasture.

将庄稼和放牧区分开绝对必要。

As they must also sprint over short distances, speed is essential.

由于他们也必须进行短跑，因此速度至关重要。

基本的;本质的；根本的

Most authorities agree that play is an essential part of a child's development.

大多数权威人士都同意，玩耍在孩子成长过程中起着非常重要的作用。

In this trial two essential elements must be proven: motive and opportunity.

在这次审讯中，必须证明两个基本因素：动机和时机。

（某学科的）基础，基本知识

the essentials of everyday life, such as eating and exercise.

饮食、锻炼等日常生活的要素

This has stripped the contest down to its essentials.

这就使比赛精简到最基本的环节。