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）
祝你英语学习愉快~加油~