First this paper analyses weighted deviation model ( wdm ) put forward by len swanson & martha l . stocking . it is found that when the constraints are made up of question numbers , question grades and other information with different dimensions , the calculated values of dl , du cannot be compared . then the wdm model is further improved and the constraints of the model are simplified in the way that only the question grades are strictly constrained while other constraints are reflected by the distribution of grades 首先，本文对lenswanson & marthal . stocking提出的离差加权模型( weighteddeviationsmodel ，简称wdm模型)进行分析，发现当约束条件既有题数，又有题分和信息量时，由于各约束条件的单位(量纲)不同，根据约束条件计算出的d _ l _ j ， d _ u _ j的值不可比。
They get all their chawing by borrowing ; they say to a fellow , " i wisht you d len me a chaw , jack , i jist this minute give ben thompson the last chaw i had " - which is a lie pretty much everytime ; it don t fool nobody but a stranger ; but jack ain t no stranger , so he says 他们嚼的烟都是借来的他们对一个家伙说： “杰克，借口烟嚼嚼，怎么样。我刚把我最后一口烟给了朋汤浦逊”而这是谎话。往往每回都如此，除非是生人，这骗不了谁，而杰克可并非生人，他就说： “你给过他一口烟，真是这样么？
