[问答题]
State Huygen's princ9guk,): ze4 xvmxy ry*j7/0tq6bzdrmmm/ osh- c/ft2 iple.
参考答案: Every point on a wave front can be considered as a source of tiny wavelets that spread out in the forward direction at the speed of the wave itself. The new wave front is the envelope of all the wavelets - that is, tangent to all of them.
