红外夜视镜在美国对伊拉克反美武装力量实施的夜间打击中起到重要作用，红外夜视镜是利用了(    )

对焦耳定律的理解，下列说法正确的是（   ）

如图，C为⊙O直径AB上一动点，过点C的直线交⊙O于D，E两点，且∠ACD=45°，DF⊥AB于点F，EG⊥AB于点G，当点C在AB上运动时．设AF=x，DE=y，下列中图象中，能表示y与x的函数关系式的图象大致是（   ）

    If(如果) you don't like reading books, this is for you.

    Have a few laughs (笑声). Sit down with a book of jokes, a picture book or a funny story- book first.

    Ask around. Ask your friends or your teachers about interesting books.

    Find new interests. After reading, you may find an interest in something new.

    Go to the library. Don't be shy (害羞) about asking a librarian (图书管理员) a question like, “Do you have any books about soccer?”

    See the world (世界). When you want to know or see something, you can open the book about it.

    Try to read, you can find there is a lot of fun in books.