Tom can play the piano but he can`t play it perfectly. 或者 Tom can play the piano but he can`t play it very well. (在我看来,这一句有很多翻译方式,你可以翻译成弹得不完美,如我做的第一句的翻译,还可以是不熟练的not practiced)
Are you kind to kids? Are you friendly to kids? Can you get well along with kids? (这一句也有很多翻译方式,多尝试吧)