并不是所有的处在互补分布中的音位都是音位变体，能举个例子吗？再解释一下

互补性分布 Complementary distribution

• Where oral vowels occur, nasal vowels do not occur, and vice versa. In this sense, the phones are said to complement each other or to be in complementary distribution(互补分布，即这两个只能替代出现).  

  Aspirated and unspirited voiceless stop consonants are also in complementary distribution.(送气音和不送气音也是互补)

• In general, the allophones of a phoneme are in complementary distribution-never occurring in identical environments. (phonological rules) ← 通常，一个phoneme的allophones都是互补分布的（音标写法上是没区别的）

• Complementary distribution in English reading and writing → 大小写字母也是互补分布

这样？

不一定对...