I can't open the lock.There must be ___ key taht will open it.

问题描述:

I can't open the lock.There must be ___ key taht will open it.
a.some
b.other
c.certain
d.some other
为什么选d

因为他已经在用一把钥匙在开锁了,但没打开.他想应该有另外的钥匙可以打开.some 表示某个,other 表示其它.