HSK 7–9 · noun
劲
strength; energy; force
他干活特别有劲，从不喊累。
Tā gàn huó tèbié yǒujìn， cóng bù hǎn lèi。
He works with great energy and never complains of being tired.
箱子太重了，你得使劲推。
Xiāngzi tài zhòngle， nǐ de shǐjìn tuī。
The box is too heavy; you have to push hard.
他今天特别有劲，跑得很快。
Tā jīntiān tèbié yǒujìn， pǎo de hěn kuài。
He is especially energetic today and runs very fast.
这个箱子太重，搬起来很费劲。
Zhège xiāngzi tài zhòng， bān qǐlái hěn fèijìn。
This box is too heavy; it's very strenuous to lift.