The baby is so small that I can't leave him by itself .一句中为什

leave one by oneself 把某人独自留下,是固定搭配
再问： 那为什么不是leave him by himself 呢？
再答： one 指某人，他当然就him …… himself
再问： 可是原句用的是leave him by itself ,为什么不是leave him by himself 呢？
再答： 是有点特别，也许是打错了吧