1.just作副词表示：只是、仅仅、正好，恰好的意思。多用于完成时态中，置于动词与助动词之间。
回答问题时，用just显得语气比较委婉，只不过，仅仅。
例句1：I didn't mean to upset you. It's just that I had to tell somebody.
我本不想烦你，只是我非得找个人说说。
例句2：This essay is just not good enough .
这篇散文实在是不够好。
2.only作副词表示：只、只有、仅、仅在...情况下(或地点等)、只不过、仅...而已。常位于所修饰的动词、短语或从句前
only更强调唯一，只有，惟有。这两个词作副词表示 “仅、只”可以换用，并且都放在它们所修饰的成分之前。
例句1：We were the only people there.
我们是唯一在场的人。
例句2：You only have to look at her to see she doesn't eat enough.
你只消看一眼就知道她进食不够多。
just和only是英语中特别常见的两个词，他们俩表示的意思也差不多，所以常常容易混淆。1.Just的定义
①Recently
Just可以用在动词之前，表示刚做过某件事，比如：
Be careful— I just washed the floor, and it’s still wet.
( I washed the floor a few minutes ago.)
小心点，我刚刚才拖了地，还是湿的。
He just finished a big project.
(He finished the project very recently.)
他刚刚才完成了一个大项目。②只，仅仅
I thought you were hungry, but you ate just half of your sandwich.
我以为你饿了，结果你只吃了半个三明治。
2.Only
Only在大多数情况下可以和Just互换。
Only two students came to class on the day before Christmas.
= Just two students came…
My kids only use the internet for schoolwork, not for playing games.
= My kids just use…
如果Just表示“刚刚”，它们就不能互换。注意在不同语境下的just：
*--- Did you clean the whole house?
--- No, I just washed the floor.(I only washed the floor.)
*---Why is the floor wet?
--- Because I just washed it.（不能用only替代）
注意在不同位置中的just：
I just ate two pieces of pizza.
我刚吃了两块披萨。
I ate just two pieces of pizza.
我只吃了两块披萨。
理解这个，你就能很好区分just和only的区别了。
