单项选择题
A．To attract more sea animals to the testing site. B．To drive dangerous sea animals away from the testing site. C．To help trace the sea animals being tested. D．To determine how~ sea animals communicate with each other.
A．He accused them of the theft. B．He raised the rents. C．He refused to prolong their land lease. D．He forced them to abandon their traditions.
A．They were frightened and distressed. B．They swam away when the speaker was turned on. C．They swam closer to "examine" the speaker when it was turned off. D．They didn’t seem to be frightened and kept swimming near the speaker.