Question

They were all very tired, but _______ of them took a rest.

A．none

B．all

C．both

D．either

Answer 1

考查不定代词的用法。并列句的前面有all，说明超过二人，排除C、D选项；连词用了but，有转折的意思，说明累却不休息，因此后面要用否定词。故选A。