1、essential

絕對必要的;必不可少的;基本的

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

將莊稼和放牧區分開絕對必要。

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

由于他們也必須進行短跑，因此速度至關重要。

基本的;本質的；根本的

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

大多數權威人士都同意，玩耍在孩子成長過程中起著非常重要的作用。

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

在這次審訊中，必須證明兩個基本因素：動機和時機。

復數名詞（某學科的）基礎，基本知識

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

飲食、鍛煉等日常生活的要素

This has stripped the contest down to its essentials.

這就使比賽精簡到最基本的環節。

2、connection

關系;聯系

There was no evidence of a connection between BSE and the brain diseases recently confirmed in cats.

沒有證據表明瘋牛病與最近確診的貓類腦病有關聯。

The police say he had no connection with the security forces.

警方說他與安全部隊沒有關系。

關于;與…有關

I am writing in connection with Michael Shower's letter.

關于邁克爾·肖爾的來信，現復信如下。

13 men have been questioned in connection with the murder.

有13名男子因謀殺案受到盤問。