27（）

A．the working system of the electric plates in the eel is the most effective
B．the working system of the electric plates in the eel is far inferior to those in the torpedo
C．compared with those in the torpedo, the working system of, electric plates in the eel is more direct and efficient
D．compared with other electric fish, the eel possesses much more electric plates

A．the lights were directly related to some basic "drives"
B．the sight of the lights was interesting
C．they need not turn back to watch the lights
D．they succeeded in "switching on" the lights