如图，已知▱ABCD的对角线BD=4cm，将▱ABCD绕其对称中心O旋转180°，则点D所转过的路径长为（　）

    One day, a little schoolboy went home with a pain in his stomach.

    "Well, sit down and 1 a cake," said his mother."Your stomach 2hurting because it's empty.It'll be all right when you've got something in it."

    Five minutes later, Dad came home 3 the office.And he said he had a headache.

    "That's because your head is 4," said his clever son."You'll be all right if you have got 5 in it." His dad and mum laughed.

名著阅读。

写出下列形容词的比较级

long____ high____ big ____ small____ thin  ____