1. A method of analyzing grammar using a part-of-speech tagged parser with a template-based computer-assisted learning system comprising the steps of: preassigning words and phrases of an input sentence with part-of-speech tags; regarding any phrase preassigned with a part-of-speech tag as one word; setting a probability of preassigned words having a given tag as 1; setting a probability of nonassigned words having a given tag as 0; obtaining a plurality of grammar trees; finding a combination within said plurality of grammar trees to maximize probability of the final grammar tree being any of a grammar tree with the following formula to choose the one with largest probability P tree : 3 P tree &af; ( T ) = &Product; rule i &it; inT &it; &it; P rule i &CenterDot; &Product; tag j &it; of &it; &it; word j &it; inT &it; &it; ( P &af; ( tag j | word j ) ) 2 where P rule i denotes the probability of a rule to take on rule i, P(tag j &verbar;word j ) is the probability of the word j being assigned to part-of-speech tag be tag j.