The old view of it was rather mechanical: pull the interest-rate lever up and, via Banks and bond markets, lending and spending would fall; pull it down and they would rise.

老观点相当机械的认为：提高利率水平，借贷和支出将通过银行和债券市场得到削减，反之亦然。

youdao

Pull down the left and the middle lever and then push the button to get an elevator.

拉下左边和中间的杠杆，然后按下按钮，得到一个电梯。

youdao

And now we pull down on the lever.

现在我们推动了杠杆。

youdao

So if you've ever seen or used an old school typewriter, you might recall that when you're typing something out on an old mechanical typewriter, - when you like hit the char-- when you hit the enter key to move the head back to the left hand side to the next line or you would pull down some lever, it was really a two part process.

如果你们有谁曾经看过或用过老式打字机，可能还记得，当你在,这种老式打字机上打字的时候，当你-,敲入回车键，跳转到,下一行的最左边，或者,拉一下杆，这个需要两步走。

哈佛公开课 - 计算机科学课程节选