同化：t 碰到 p

In fluent speech, if one word ends in a /t/ sound and the next word begins in a /p/ sound, the /t/ is pronounced slightly differently. In fact, we pronounce it as if it were almost a /p/ sound.

和第 24 课 n 碰到 p 变成 m 一个道理：嘴唇提前合上准备发 p，t 就被带成了 p。Tim 用慢动作展示：说 white 的结尾时，路人的嘴唇已经闭上了。

到这里，同化的规律可以总结成一句：舌尖音 t / d / n 遇到嘴唇音 p / b / m，分别变成 p / b / m；t / d 遇到舌根音 k / g，变成 k / g。