单项选择题
Passage one Questions 27 to 30 are based on the passage you have just heard.
A．Their racial attitudes improved. B．Their test scores rose gradually. C．They grew bored of each other. D．They started doing similar activities.
A．suppresses creative thinking B．guarantees academic freedom C．creates conflicts among colleagues D．is a sign of age discrimination
A．Only one dolphin was able to see the light. B．The male dolphin received more rewards. C．Both dolphins were put in the same tank. D．The lever was beyond the dolphins’ reach.