在盒盖的背面画一个椭圆。

Draw an ellipse on the box.

youdao

在第二堆上面的卡片上用红色的铅笔画一个椭圆。

Pick up the red pencil and draw an oval on the card of the second pile.

youdao

选择椭圆选框工具，然后在欢迎图片下方画一个椭圆。

Select the elliptical Marquee Tool, and then make an elliptical selection at the bottom of your welcome image.

youdao

Well, it was not very hard for me to draw this red blood cell here, it's just an oval, and one reason I draw it like an oval, is that that's basically what it looks like if you look at it.

我可以很容易的画出,一个血红细胞,就画个椭圆足矣,因为它看上去就是这个样子的

耶鲁公开课 - 生物医学工程探索课程节选