Are they American cars?（改为单数）

Are they American cars?（改为单数） 1.They're american cars 改为单数 2.They are japanese actresses 改 They are English cars.(改为单数形式) Are they American cars? They are American teachers(改为单数句) are they american students?改为单数形式 These are American cars 改成单数 These are American cars（ 改为特殊疑问句）怎么写? These are English cars.（改为单数句） are those japanese cars?改为单数形式 Those are English cars.改为单数是什么? those are cars 改为单数句