more careful 和 the more careful 有什么区别？

more careful指一个人比另一人细心。

比如：
Jane is more careful than Helen.
Jane比Helen更细心。

the more careful指两人中更细心的一人，因为只有两个人，所以用the，有点最高级的意思。

比如：
Jane and Helen are twins. Jane is the more careful one.
Jane和Helen是双胞胎。Jane是更细心的那个。

more careful表示比...更认真
如：Tom is more careful than Mike.
Mary is a more careful girl than Jane. the more careful有两种含义：
1.表示两者当中较认真的那个。
如：Jenny is the more careful (of the two).
2...越认真...(越...)
如：The more careful ,the better.