Noun + 大大 + 的
大大 (dàdà) is an adverb or adjective meaning "greatly," "widely," or "very much." Through reduplication of 大, it intensifies the sense of largeness or extent. It is often used to describe eyes opened wide, as in 眼睛大大的 (eyes wide open).
听到这件事,他把眼睛睁得大大的。
Tīng dào zhè jiàn shì, tā bǎ yǎnjīng zhēng de dà dà de.
Hearing this, he opened his eyes wide.
这次改革大大提高了工作效率。
Zhè cì gǎigé dà dà tígāo le gōngzuò xiàolǜ.
This reform greatly improved work efficiency.
新政策大大改善了居民的生活条件。
Xīn zhèngcè dà dà gǎishàn le jūmín de shēnghuó tiáojiàn.
The new policy greatly improved residents' living conditions.