A r（） is often seen as part of a word， but it can never stand by itself although it bears clear， definite meaning.

Clear [1] and dark[]are allophones of the same one phoneme 1 .They never take the same position in sound combinations， thus they are said to be in c（） distribution. 点击查看答案

In the course of time， the study of language has come to establish close links with other branches of s（） studies， such as sociology and psychology. 点击查看答案