心猿意马 ------- carry fire in one hand and water in the other

例句：
A: I don't know why Tome never did anything successful.
我不知道为何汤姆做任何事都不曾成功。
B: It's quite easy to know, for he often carries fire in one hand and water in the other.
这相当容易知道，因为他经常心猿意马。

同义词：
run with the hound and hold with the hare