在开发利用金属矿物和海水资源过程中，下列说法不正确的是 A．工业上可用电解法冶炼

Long long ago,there was a swan(天鹅)with golden feathers(金羽毛). She lived in a lake. A woman
lived in a small house 1 the lake with her two daughters. They were very poor. They worked hard all
yearround, 2  still, they lived a hard life and sometimes they even didn't have enough _3 to buy food.
    The swan was 4 to see that. She said to herself, "I'11 give one of my    5   to them each day , then
they can live a happy life with the money selling my feathers. "That evening , she 6   to the poor
woman's house and left a golden feather  on the table without saying 7 . From then on,the swan came
every day and gave them a feather. The woman was very happy because their life was much 8 than
before.But day after day, the woman became greedy(贪婪的). She said to her 9 ,"The swan may fly
away one day. If so , we will be poor again. We should take all 10 feathers when she comes next time. "
    "Oh no,Mom!"cried the daughters,"This will 11 the swan. She helps us a lot ! "But the mother wouldn't
listen. When the 12 came as usual, the mother caught her and took all her feathers. But suddenly, the
golden feathers 13 chicken feathers.
    Then , the golden swan said , "Poor mother , I came to 14   you, but you wanted to kill me.Now,
I am leaving and will    15    come back. Never be greedy! " With these words , the swan flew away.