【Ayoungcollegestudentthoughtthathechosethewrongmajor（专业）atacommoncollege，sohedrankeverydayanddidn'tstudyatall．Hebecamemoreandmorefrustrated（挫败的）．ButhewasneverabsentfromProfessorYang'sbiolog】

　　A young college student thought that he chose the wrong major （专业） at a common college，so he drank every day and didn't study at all．He became more and more frustrated （挫败的）．

　　But he was never absent from Professor Yang's biology class．He liked the course．Besides，Yang's class was so interesting that he always listened carefully，never caring about whether the other students were paying attention or not in class．Once he put a note in the homework he handed in，saying："Professor，it is said that today's college students are cheaper than potatoes．Do you agree？"

　　That day Professor Yang sent for him after class．When he came，he found the professor at a table with a plate of food．They drank happily with their meal．

　　When they became half drunk，the professor produced a small potato that was sprouting （发芽的）．"Do you know how much this costs？"he asked the young man．"It's soft but poisonous （有毒的）．Nobody will take it even if it's free．"He then threw the potato away．The professor then showed him another potato．It was half the size of a football and perfectly round．"This potato is organic （有机的）．It is not only large and fresh but also free of pollution．It is in high demand and quite expensive．"

　　The young man was impressed by what he'd heard．"Besuchapotato，"said the professor．

　　41．The college student felt frustrated because___．

　　A．he liked drinking a lot

　　B．he didn't like his major

　　C．he studied at a common college

　　D．he didn't like his professors

　　42．What did the student look like in Professor Yang's biology class？___

　　A．He was interested in his class．

　　B．He sometimes was absent from class．

　　C．He never paid attention in class．

　　D．He never went to his class．

　　43．Professor Yang showed the student two different potatoes to tell him that___．

　　A．potatoes were not cheap at all

　　B．some soft potatoes we