fall down on one's back

As we were walking down the steps, I didn't see the last one. My right foot came down on the steps edge and I began to fall.

走下楼梯时，我没有看到最后一个台阶，我的右脚踏在台阶的边缘，我跌倒下去。

It was still moving about so I reached down and touched it on the wing causing one of the pins to fall out.

它仍在舞动，所以我伸手去抓住它，触摸舞动着的它，而使一个直针脱落了下来。

We can meditate in a number of different positions - on a cushion, on a bench, on a chair or even lying down (though I don't recommend this one as it is too easy to fall asleep).

我们可以多种姿势——在坐垫上，在长椅上，在椅子上或者直接躺在床上(我不提倡这种，因为那样极易睡着。)