4 sentences

1. 那个小伙干活非常卖力。

   nà gè xiǎo​huǒ gàn​huó fēi​cháng mài​lì.

   That lad works very hard.

   Source: Dong Chinese Dictionary

2. 他为了赢得比赛，训练得非常卖力。

   tā wèi​le yíng​dé bǐ​sài, xùn​liàn de fēi​cháng mài​lì.

   He trained very hard to win the race.

   Source: Dong Chinese Dictionary

3. 他一心想出人头地，所以工作非常卖力。

   tā yī​xīn xiǎng chū​rén​tóu​dì, suǒ​yǐ gōng​zuò fēi​cháng mài​lì.

   He is determined to stand out, so he works very hard.

   Source: Dong Chinese Dictionary

4. 为了保住这个月的奖金，他工作得非常卖力。

   wèi​le bǎo​zhù zhè​ge yuè de jiǎng​jīn, tā gōng​zuò de fēi​cháng mài​lì.

   In order to keep his bonus for this month, he worked very hard.

   Source: Dong Chinese Dictionary