Least?
Least is an adjective that means the smallest amount:
Least是一個形容詞，意思是“最小得;最少得(little得很可以)”。
We need the least amount of friction possible.
我們需要盡專家少得摩擦。
Lest
Lest is a conjunction that refers to averting or circumventing something
Lest則是一個連詞，表示“回避或回避某事;唯恐，以免，只怕”
Memorial Day is a holiday to reflect on past wars lest we forget the soldiers who fought for our freedoms.
烈士紀(jì)念日是一個緬懷過去戰(zhàn)爭得節(jié)日，以免我們忘記那些為我們得自由而戰(zhàn)得戰(zhàn)士。
At Least
至少，起碼
The English expression at least can be used before/with a verb, signifying that something can be done despite circumstances, or before/with a number/quantity, signifying a minimal quantity.
在英語表達(dá)中通常用在動詞前或者動詞連用，表示不管情況如何都專業(yè)做某事;用在數(shù)量前，表示最小值
Although ill, at least I am here.
雖然我生病了，至少我還在這兒。
I wish to buy at least three presents.
我希望我能買至少3個禮物。
最后我們來總結(jié)一下
least是一個形容詞，
意思是“最小得;最少得”，也就是little得很可以
lest則是連詞，
“唯恐，以免”得意思
他們兩個只是長的像而已
而“至少”則是at least
