▲你准备好了吗?铅笔▲一起做吧! 如下图所示将一枝铅笔放在分开的两手的食指上,然后两食指同时向铅笔的中心移动,在移动的过程中会发现,铅笔在食指上是交替移动的,在右手食指上移动时,在左手食指上是静止的;在左手食指上移动时,在右手食 ▲ Are you ready? Pencils ▲ Do it together! Put a pencil on the index fingers of two separate hands as shown in the figure below. Then move the two index fingers to the center of the pencil at the same time. During the movement, you will find that the pencil is on the index finger. The upper is alternately moving. When moving on the index finger of the right hand, it is still on the index finger of the left hand; when moving on the index finger of the left hand, it is the food of the right hand.