Question

—Which one can I take?—You can take ________ of them；I’ll keep none. A．both B．any C．

—Which one can I take?—You can take ________ of them；I’ll keep none. A．both B．any C．either D．all

Answer 1

• Both of them

• both of them的意思是他们俩.只要指的是两个,都可以用both of them
  三个（包括三个）以上就不可以了.
  

• all of them就是三个以上的.
  如：
  Both of the workers are happy.两个工人都很高兴.
  Both of them are not workers.他们俩并非都是工人.
  

Answer 2

D 解析　句意为：——我能拿哪一个？——你可以全拿走，我一个也不留。根据“I’ll keep none.”可知，有三个或三个以上的东西，而且可以全部拿走，所以选D项。