Now without taking your hands from the ground, try to straighten your knees.

They all tried, but their feet caved in every time they straightened their knees.

He was mortally wounded, but he straightened his knees and fired.

While sitting on a chair, straighten your knees to raise your feet.

He slowly straightened his knees to move nearer.

Each time he straightened his pudgy knees it was apparent that they were trembling.

He straightened his knees, until he was standing, more or less easily.

But as she straightened her knees, took her own weight, she realized that there was no way out.

Reaching down, I caught hold of a loaded saddle with each hand and straightened my knees.

I kept having to say, 'No, no, don't really straighten your knees.