1. A method of identifying a semantic structure from a text, the method comprising: identifying two semantic entities from a first portion of the text; a processor searching a table using the two semantic entities to locate an entry that lists all entities that connect the two semantic entities to form a semantic structure; the processor forming a candidate semantic structure, wherein the candidate semantic structure comprises a parent semantic entity taken from the entry of the table where the parent semantic entity was not identified from the text and where the two semantic entities identified from the text are child semantic entities of the parent semantic entity in the candidate semantic structure; generating a semantic score for the candidate semantic structure based on the probability of a child semantic entity given a parent semantic entity in the candidate semantic structure; applying a penalty factor to the semantic score because the parent semantic entity was not identified from the text; generating a transition score for the candidate semantic structure by generating a separate transition probability for each pair of semantic entities that appear on a same level in the candidate semantic structure wherein generating a transition probability comprises dividing a count of the number of times the pair of semantic entities appear in a particular order on the same level in training data by a count of the number of times the pair of semantic entities appear on the same level in the training data; generating a syntactic score for the candidate semantic structure based in part on the position of a word in the text and the position in the semantic structure of a semantic entity formed from the word; combining the syntactic score, the transition score, and the semantic score to form a combined score for the candidate semantic structure; deciding not to prune the candidate semantic structure from further consideration based on the combined score; identifying the parent semantic entity from a second portion of the text; removing the penalty factor from the semantic score for the candidate semantic structure because the parent semantic entity has been identified from the text; combining the syntactic score, the transition score, and the semantic score with the penalty factor removed to form a new combined score for the candidate semantic structure; and deciding not to prune the candidate semantic structure from further consideration based on the new combined score.