relieve [ri'li:v]liev=lev
【根】lev＝to raise（升;举;提）,light（轻的）
lift-lev
to remove or reduce an unpleasant feeling or pain:
to make a problem less serious
to make sth less boring, especially by introducing sth different
to replace sb who is on duty
to free a town, etc. from an enemy army that has surrounded it
~ yourself a polite way of referring to going to the toilet
vt. 减轻；使不单调乏味;解除(痛苦、忧虑等)；解围；使放心；换…的班；[委婉语]解除职务[(+of)]

例句
The fund is for relieving distress among the flood victims.
这笔款项是用于解救洪水灾民的困苦的。
Knowing the truth relieved the anxious parents.
知道事情的真相使焦急的父母大为宽心。
The guard will be relieved at midnight.
守卫将在半夜换班。

relief [ri'li:f]
n.减轻，解除；安慰; 救济

alleviate[ə'li:vieit]
to make something bad such as pain or problems less severe:
vt. 减轻，缓和

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In other words, wealthy people, in an effort to alleviate penury, would create a savings bank.
换句话说,富人们要扶危济困,便建立了储蓄银行。

elevate['eliveit]
~ sth (into sth) (formal) to give sb/sth a higher position or rank, often more important than they deserve
(technical or formal) to lift sth up or put sth in a higher position
(technical) to make the level of sth increase
(formal) to improve a person's mood, so that they feel happy
vt. 提升；举起；提升…的职位;提高(嗓子,道德品质,信心等);振奋情绪等

例句
Earth movements in the past elevated great areas of the seabed.
地球过去的运动使海底大片地区隆起。
He was elevated to the position of captain.
他被提升为船长。
Good books may elevate the mind.
好书可以提高思想修养。

elevator['eliveitə]
(AmE) = LIFT
a place for storing large quantities of grain
a part in the tail of an aircraft that is moved to make it go up or down
n. 电梯；升降机；升降舵；起卸机

例句
Many department stores have both elevators and escalators.
许多百货公司既有电梯又有自动扶梯。

levity ['levəti]
Lightness of manner or speech, especially when inappropriate; frivolity
Inconstancy; changeableness
n. 多变；轻浮；轻率；不稳定

例句
His remarks injected a note of levity into the proceedings.
他的话将一丝轻率带入了议事过程中。
Your levity is unseemly at this time.
在这种场合,你的轻率举动是不得体的。

leaven['levn]
a substance, especially YEAST, that is added to bread before it is cooked to make it rise
~ sth (with sth) (formal) to make sth more interesting or cheerful by adding sth to it:
vt. 使发酵；使渐变;影响
vi. 渐变
n. 酵母；酵素；潜移默化的影响

例句
Biscuits and crackers are chemically leavened.
饼干和脆饼干是用化学方法发酵的。
The chairman leavened the dull meeting with a few jokes.
主席讲了几个笑话来活跃沉闷的会议。