修一条水渠，如果每天多修8米，可提前4天完成，如果每天少修8米，要推迟8天完成，求这条水渠的长度？

①m∈3，4）

②abcd∈0，e⁴）

③a+b+c+d∈ $e^5+\frac{1}{e}-2,e^6+\frac{1}{e^2}-2$

④若关于x的方程f（x）+x=m恰有三个不同实根，则m取值唯一．

则其中正确的结论是（   ）

《青松》的作者是（    ）

    Once, ____ old lion loved a girl, so he went to the girl's parents with many ____ (present) and asked them to marry (嫁）her to him.

    The parents didn't like the idea of ____ (give) their daughter to the lion but they didn't want ____ (make) the lion angry.

    Finally, the father said, "We are glad to marry ____ daughter to you, but can you promise ____ (move) away your claws (爪子) and teeth? "The lion loved the girl very much, ____ he moved away his claws and teeth.

    On the ____ (two) day, when he came to the parents, they just laughed at him and drove him away.

    The lion was angry, but he didn't have claws and teeth. He ____ (realize) that he shouldn't believe (相信）them ____ (easy) and give up his claws and teeth.