We have already learned the reduplication of verbs and reduplication of adjectives in Chinese language. And we have also learned what the measure words are. Now why not learn a bit about the reduplication of measure words.
Reduplicated measure words denote the inclusion of the entirety without exception. It is used to emphasize that all the individual members of a group share the same qualities or exist in the same state. See the example below:
tāmen gè gè dōu xǐhuan yòng kuàizi
They all like to use chopsticks
Similarly some nouns like 人，年 and 天 can also be reduplicated for the same purpose:
Xiànzài rén rén dōu guānxīn běijīng de lǜhuà
These days everyone is concerned about Beijing’s greenery.
However please note that reduplicated measure words and nouns cannot be used as objects. The sentence 我告诉人人 would be incorrect.