One or two apples are... 

One apple or two is/are...  

There is/are one student or two.

There are one or two students.

one or two 作定语，后面的名词是复数，谓语动词用复数：

There were one or two suspicious looks from nearby.  

附近有一两个人投来怀疑的目光。

来自柯林斯例句

Already, one or two critics have begun to muddle the two names.  

一两个评论家已经开始把这两个名字弄混了。

来自柯林斯例句