2010年11月12日至27日,第16届亚运会在中国广州进行,运动员们奋勇拼搏,敢于争先,发扬更快、更高、更强的奥林匹克精神,创造了优异的运动成绩。下列几种比赛项目中的研究对象可视为质点的是( )
A:百米赛跑中研究运动员冲刺撞线时
B:跆拳道比赛中研究运动员动作时
C:帆船比赛中确定帆船在大海中位置时
D:在撑杆跳高比赛中研究运动员手中的支撑杆在支撑地面的过程中的转动情况时
选择正确的图画,把图画的序号填在括号内
①This is a monkey. It has a long tail. It's thin. ____
②Look at the giraffe . It has long legs and a small head. It's so tall. ____
③This is a panda.It has big eyes and a short tail. It's black and white.____
④Look at the elephant. It has a big body and a long nose. It is so fat.____
⑤I have a duck. It has a big mouth. It's small.____