Question

Want to know once and for all, we will not know what it means...

Answer 1

once
副词 ad.
1.
一次,一回
I see them once every two months.
我每两个月与他们见一次面。
2.
昔日,曾经
He once knew her, but they are no longer friends.
他以前认识她,但他们已经不是朋友了。

名词 n.
1.
一次,一回
Once is enough.
一次就够了。

连接词 conj.
1.
一旦,一经...便
Once you get into a bad habit, you'll find it hard to get out of it.
一旦染上坏习惯,想改掉就难了。
for all
1.尽管
For all her wealth, she is not happy.
她虽然很富有,但并不幸福
2.虽然

Answer 2

Once you get into a bad habit, you'll find it hard to get out of it.
一旦染上坏习惯,想改掉就难了。

Answer 3

要知道，一旦和所有，我们会不知道这意味着什么…