Let's take the situation where we take a violin string and we pluck it.

让我们设想这样一个情景,我们拿着小提琴的弦拉直它。

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Here is the pitch in--of--a string an octave higher so you can see it this way. As you probably know, if you take a long string and pluck it, it's going to take that long string a long time to pass that sort of cycle, if you will, just one pass through that cycle.

这也是个音高,一个高八度的音弦,你可以这样这样看 你们可能知道,如果你拨动长弦,长弦要经过很长时间,才能完成一个震动周期,如果你想,可以尝试下

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