国家开放大学 / 综合英语（3）
What is the main idea of the passage? _ _ _ _ _ _ _ _ _ .
A.Electric eels are potentially dangerous
B.Biology and electricity appear to be closely related
C.The modern age is an age of electricity.
D.Scientists still have much to discover about electricity
A.Electric eels are potentially dangerous
B.Biology and electricity appear to be closely related
C.The modern age is an age of electricity.
D.Scientists still have much to discover about electricity
参考答案：