有一读者问： 有这样一句话：
(1)Which is better, this one or that one?
this one or that one是否是which的同位语？或是一种独立结构？
上述句（1）是一种选择疑问句。Which is better是一特殊疑问句，this one or that one是is this one better or is that one better的省略结构。所以，上述句（1），正如一本权威著作所说，实际上是一特殊疑问句和一省略的选择疑问句的一种综合结构。再如：
(2)Which ice cream would you like, chocolate, vanilla or strawberry? （实际上相当于Which ice cream would you like? Would you like chocolate, vanilla or strawberry?）
