Is that an orange的复数形式是什么?

题目

Is that an orange的复数形式是什么?
还有吧What are these?和 They are English buses改成单数句

答案

Is that an orange
复数形式：Are those oranges?
What are these?
单数句：What is this?
They are English buses.
单数句:This is an English bus.