+ (-le了) + complement of quantity + (le了)
Specifying the quantity that has been or will be added to or removed from the object as a result of the action.
11.1 Shāngdiàn bǎ diànshì de jiàgé jiàngdī-le
Stores have lowered the price of televisions by half.
11.2 Wǒmen yídìng yào bǎ
chǎnliàng tígāo-le bǎi
fēn zhī èr.
We must increase the output by two percent.
11.3 Tā yǐjīng bǎ cài qiē-le
yí bān le.
He has already cut half of the vegetables up to now.