在生态系统中，物质和能量沿着食物链和食物网流动，一些不易分解的有毒物质能够沿食物链积累．

如图3直线上有n个点，则图中有____条可用图中字母表示的射线，有____条线段；

根据首字母或中文提示完成句子。
Tony likes talk show. But he can't s____ Chinese cooking.
Look! Tom and his family are l____ on the beach, they look happy.
We had great fun s____ in the river.
The pop singer w____ funny glasses is Johnny Dean.
I'm s____she can dance so well. She is only 7 years old.
——What e____ do you have to do?——We have to clean the classroom.
 On weekends, the shops are too c____, there are so many people in them .
——What's Lilei doing?—— He's w____ for the bus.Jenny is lazy, she n____does her homework at home.
Do you think everyone e____  their weekends?

①a是我国封建社会的繁荣时期  ②b的都城在上京  ③与c并立的两个政权是由契丹族建立的金和党项族建立的西夏  ④d的建立者是忽必烈