The lecture casts doubt on the statement presented in the reading material, which suggests people work four days a week instead of five days. He holds that the new policy will bring negative effects. In order to prove his point of view, he boils it down to three reasons.(很新颖的表达,学习!)
First, the professor contradicts the issue based on the fact that once the new policy been(改为is) carried out there will be some increased expenses applied to make up for the training and medical benefits. Still, more office space and computers are acquired to meet the demands of extra employees, and it's also cut into the company profits. That is, the new policy will not be beneficial.
Meanwhile, another difference between the lecture and the reading passage emphasizes whether the policy do good to reducing(reduce) the unemployment rate. The professor points out that employer may tend to raise their expectations of four-day employees rather than recruit new employees to avoid of(去掉of) higher expenses. Therefore, not only no additional work will be created but employees will be unpleasant.
Finally, four-day policy will probably harm the advancing for the employees who take this policy. Because a range of companies prefer to five-day employee for their entire week work.
Thus it can be inferred that the professor challenges the passage by giving reasons as to why he thinks the new policy won't work.