单项选择题
According to biologists, animal populations at a given time are _________ by food supplies at that time.
单项选择题 The boy slipped out of the room and headed for the swimming pool without his parents'__________.
单项选择题 She _________ being spied on when she was sunbathing in the garden.
单项选择题 A friend is a person with whom I may be _________ Before him, I may think aloud.
