1、master

主人;雇主;老板

My master ordered me not to deliver the message except in private.

我的主人命令我務必私下里傳遞消息。

In 1777 several northern states encouraged white masters to free their slaves for military service.

1777年，北方的幾個州鼓勵白人奴隸主解放奴隸，讓他們參軍。

專家;能手;高手

She was a master of the English language.

她是英文高手。

He is a master at blocking progress.

他特別擅長充當攔路虎。

掌握;精通

Duff soon mastered the skills of radio production.

達夫很快掌握了廣播節目制作的技能。

Students are expected to master a second language.

學生應該掌握一門第二語言。

2、friction

矛盾;不和;爭執

Sara sensed that there had been friction between her children.

薩拉感覺到她的孩子之間有過爭執。

The plan is likely only to aggravate ethnic frictions.

這一方案很有可能只會加劇種族沖突。

摩擦力

The pistons are graphite-coated to reduce friction.

活塞上涂了一層石墨以減小摩擦力。