* compel
v. 強(qiáng)迫，逼迫
The law will compel employers to provide health insurance.
這項(xiàng)法律將強(qiáng)迫雇主提供健康保險(xiǎn)。
She felt compelled to resign because of the scandal.
因?yàn)檫@個(gè)丑聞，她感到必須辭職。
* compulsion
n. 強(qiáng)烈的欲望，沖動(dòng)
Leith felt an overwhelming compulsion to tell him the truth.
利思感到有一股強(qiáng)烈的欲望要把實(shí)情告訴他。
* compulsory
a. 強(qiáng)制的，強(qiáng)迫的
It is compulsory for all motorcyclists to wear helmets.
所有騎摩托車的人都必須戴頭盔，這是強(qiáng)制性的。
English is a compulsory subject at this level.
英語(yǔ)在這一級(jí)次是必修科目。
* optional
a. 可選擇的

* expel
v. 開除
Two girls were expelled from school for taking drugs.
兩個(gè)女生因吸毒而被學(xué)校開除。
The main opposition leader was expelled from her party.
主要反對(duì)黨的領(lǐng)導(dǎo)人被開除出黨。
* propel
v. 推動(dòng)，推進(jìn)，驅(qū)動(dòng)
a boat propelled by oars
用槳?jiǎng)澋拇?br />* propeller
n. 推進(jìn)器，螺旋槳
* repel
v. 排斥
Two positive charges repel each other.
兩個(gè)正電荷相互排斥。
a lotion that repels mosquitoes
驅(qū)蚊液
The army was ready to repel an attack.
軍隊(duì)已準(zhǔn)備好擊退進(jìn)攻。
The smell repelled him.
這氣味讓他反感。