【简答题】(Passage 2, Lines 1-3, Para. 3) Them we fed them four unidentified samples of cola on at a time, regular colas for the one group, diet versions for the other.
【简答题】Questions 17 to 20 are based on the following passage. At the end o f the passage, you will be given 20 seconds to answer the questions. Now,, listen to the passage. By what means did Joe think he cou...