Stack you hands on top of each other, with top hand "locked" to the bottom hand with the thumb.

双手叠起，用上面的那只手的大拇指扣住下面的手。

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Place the other hand on top.

VOA: special.2009.08.11

Look in the packet at this letter near the top of the right-hand side of the page.

看一下这封信的,右手边最上面。

耶鲁公开课 - 弥尔顿课程节选

Now look at page 671 again on the top of the left-hand column.

现在请再看671页左边栏的最上面。

耶鲁公开课 - 弥尔顿课程节选

So most of the work is done by the top hand, with the bottom hand lending support.

BBC: Introduction

Current broomstick users, by moving their putters away from their chest and creating an un-anchored fulcrum with their top hand, could still make a pendulum stroke.

WSJ: Don't Make Golf Too Easy | Golf Journal by John Paul Newport

What do you think the symbol in the top left hand corner is?

BBC: A Point of View: The euro's strange stories