阅读理解

    This story is about a young man. He worked very hard at his lessons, so he was too busy to have a rest. At last, he couldn't go to sleep every night. When he went to bed, he closed his eyes and tried to sleep.But the more he tried, the more he stayed awake.

    After a while, he decided to visit the doctor."I just can't go to sleep at night. What should I do?" "I have a suggestion,"said the doctor, "try counting numbers. By the time you reach one thousand, you'll be asleep. I'm sure of it. The next day the man returned to the doctor's office."well," said the doctor, "How are you today? Did you try my suggestion?"

    The man still looked tired, "Yes,"he said, " I tried counting one, two, three…up to one thousand. But when I reached five thousand and sixty-nine, I began to feel sleepy. I had to get up and drink some tea so that I could go on counting up to one thousand, but then I still couldn't fall asleep.

如图所示的长方体中，AB=2 $\sqrt{6}$ ，AD= $\sqrt{5}$ ， $C{C}_1$ = $2\sqrt{3}$ ，E、F分别为 $A{A}_1,A_1{B}_1$ 的中点，则异面直线DE、BF所成角的大小为（   ）

阅读理解A
    I'm Linda．I can't find my keys．I lost them this morning．There is a Lost and Found box in our classroom．My keys may (可能)be in the box．
    Oh, there are many things in the box．This is a pencil box．What color is it? It's yellow．That is a white eraser．And what's that? It is a watch．A picture of a CD is on it．It's Sara's．Wow! I find my keys．One is to my classroom，and the other (另一个)is to my house．That green cup is Jack's．This baseball is his，too．I will(将)ask him to take his things．Three rulers, two pencils and two nice pens are also in the box．Whose are they? I don't know．
根据材料内容判断正误。

下列关于DNA复制的叙述，正确的是

有关基因与酶关系的叙述正确的是