空格里应填though,therefore还是since?为什么?Notonlycanratlesnakessensethepresenceofanotheranimal---orahuman---buttheyapparentlycaninstantlydetermineitsdirectionandrange.

Question

空格里应填 though,therefore还是 since?为什么?
Not only can ratlesnakes ____ sense the presence of another animal --- or a human --- but they apparently can instantly determine its direction and range.

Answer 1

Not only can ratlesnakes ____ sense the presence of another animal --- or a human --- but they apparently can instantly determine its direction and range.
响尾蛇不但能判断出另一个动物或人类的存在,显然它们还能即时判断其方向和距离.
你给的三个空,什么都不能填,任何一个空都是不必填词的,填上句子就不对了