It's an either-or situation-you can take on-line classes at home or have classes in the school,

It's an either-or situation-you can take on-line classes at home or have classes in the school, but you can't do_________.
A. others B. both C. another D. either
【答案】B
【解析】
【详解】考查不定代词。句意：这是一种非此即彼的情况——你可以在家上网络课，也可以在学校上课，但你不能两者兼得。A.  others其他人；B.  both两个都；C. another 另一个；D.  either两者之一。not…both“不是两者兼有”，是部分否定，根据take on-line classes at home or have classes in the school可知，你不能两者兼得，故选B项。