月经是女孩进入青春期后，什么结构每月一次的出血现象（　　）​

2012年“六•五”世界环境日中国主题为“绿色消费，你行动了吗？”旨在强调绿色消费理念，节约资源能源，保护生态环境．草原是生态环境的重要组成部分，某草原生态系统食物网如图所示，下列能正确表示该生态系统中一条食物链的是（    ）

    This is Mike's bedroom. You can see a desk and a bed in the room. On the desk, there is a backpack and three books. One is a Chinese book, the other two are English books. There is a clock on the desk, too. You can see a baseball under the desk. On the bed there is a box. Can you guess what's in the box? Ah, it's a new computer game. It's the present(礼物) for Mike's seventh birthday.

My sister is____ young____ she can't dress herself.