If you look first at the behavior of the fly on the right, you can see that whenever it reaches the midpoint of the chamber where the two odors meet, it marches straight through, as it did before.
如果你先看看 右边果蝇的行为， 你可以看到，当它到达小室的中心点 两种气味的交汇的地方时， 它会一直走过去，就像从前一样。