F.
Le
了
is used for asking and answering questions about how long one has not done something or, in other words, time elapsed since one last did something.
Sentence Pattern:
subject + (adverb) + duration +
méi
没
(or
méi yǒu
没有
) + verb + (object) +
le
了
It is important to note that this pattern places the duration before the verb and uses
méi
没
and
le
了
in the same sentence.
Wǒ yǐjīng liǎng tiān méi(yǒu) chī fàn
le
.
我已经两天没吃饭了。
I have not eaten for two days.
Tā yǐjīng sān nián méi xué Zhōngwén
le
.
他已经三年没学中文了。
He has not studied Chinese for three years.