比较好的做法是用一个参照物，比如画一个椭圆形让火焰保持在这个范围之内，而且你可以让火苗窜到椭圆的边缘处。

It's good to use a reference for the shape, such as drawing an ellipse within which the fire will remain and you can send the flames up to any of the edges of this ellipse.

youdao

也就是说，当我们看到未颠倒的相片时，我们潜意识的会在脑海中产生类似这样的想法：“这是一个人脸，它是椭圆形的，那么我就先画一个椭圆形；头发是长而细的，那么我就画一些线条。”

Faces are ovals; I’ll draw an oval. Hair is long and stringy; I’ll draw some lines.

youdao

椭圆形的焙盘比圆形的更实用，因为椭圆形的焙盘既能放一整只鸡和一整块肉，也可以放炖菜或是汤。

Oval casseroles are more practical than round ones as they can hold a chicken or a roast of meat as well as a stew or a soup.

youdao

s plus 1s gives you this oval ellipsoid which is the bonding, and here are the antibonding, and then these are the energy levels that I have been drawing for you.

s和1s上两个电子组成的键合电子成椭圆形,这是成键，这是反键电子，这些是刚刚已经画过的能级,我也给你们画了。

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