Once harm is to the eco-system, all species will , including man himself.
A. made; be in danger
B. done; be dangerous
C. caused; be endangered
D. done; be in danger
网友回答
A. made; be in danger
B. done; be dangerous
C. caused; be endangered
(答案→)D. done; be in danger
解析：第一空短语do harm to 对…有害；第二空短语in danger处于危险中。 一旦做了对生态有害的事情所有的物种包括人类自己会处于危险中。选D