A complex sentence is a group of words which expresses two or more unified thoughts, one of which is the main or principal thought dependent on it one or more subordinate thoughts. 老师好!这里的dependent on it中的it是不是多余了?
为什么[l]和[r]遇到[s][p][t][k]之后就从voiced变成voiceless了?In English,the sounds [l] and [r],which are usually voiced,are voiceless when they follow [s][p][t][k],as in slay,pray,tray,clay. 这是为什么?