【正确答案】正确答案：Assimilation refers to a linguistic process by which a sound becomes similar to an adjacent sound.(1 point)In terms of the distance between the target and the trigger, assimilation falls into two types; contiguous assimilation and non-contiguous assimilation. Contiguous assimilation includes two subtypes; partial assimilation as in " ten bikes/ten plays" and total assimilation as in " ten mice". Non-contiguous assimilation can be showed in " discussing shortly".(2 points)Assimilation can also be divided, according to its direction, into progressive and regressive types. If the target is followed by the trigger, the assimilation is regressive as in " ten bikes" ; if the target is preceded by the trigger, the assimilation is progressive as in "branch school".(2 points)

【答案解析】解析：考查音系学中的同化现象。同化可以分为临近同化和非临近同化，根据先后顺序，也可分为逆同化和顺同化。鼻音化、齿音化及软腭化都是同化现象。