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.
6.1 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.
6.2 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.