【听第10段材料，回答第17至20题．17．Howlongwillthecourselast？A．Oneday．B．Twodays．C．Threedays．18．Whenwillthecoursebeoffered？A．Sunday，Oct.6．B．Sunday，Nov.16C．Saturday，Sept.16．1】

听第10段材料，回答第17至20题．

17．How long will the course last？

A．One day． B．Two days． C．Three days．

18．When will the course be offered？

A．Sunday，Oct.6． B．Sunday，Nov.16 C．Saturday，Sept.16．

19．What will be discussed in the course？

A．Basic concepts of the system．

B．Approaches （方法） to the study of complex systems．

C．Social and engineered systems．

20．How much will be charged for the students outside of MIT？

A．﹩350． B．﹩150． C．﹩50．