看图读一读,连线。
① ____ A. Do you like ice cream? - Yes, I like ice cream.
② ____ B. Taste the noodles, Tom. Yummy.
③ ____ C. What do you hear? I hear a cat.
④ ____ D. What do you see? I see a bird. It's yellow.
脊椎动物的运动系统中,起到支点作用的是( )
人体呼出的气体含有较多的二氧化碳,二氧化碳产生于( )