2美元是 two dollar 还是 two dollars?还是两者都行?

2美元是 two dollar 还是 two dollars?还是两者都行? 一美元是用a dollar还是one dollars 1.68美元用dollar 还是dollars? 两美元 two dollar 1美元用英文怎么说?one dollars 还是 one dollar two to two to two two翻译到底是two to two to two two还是two to two one-million dollar还是one-million dollars Here () two dollars. be动词用are还是is? 是two hurdred还是two hundreds 是two hundred还是two-hundred 是TWO HUNDRED 还是 TWO HUNDREDS ? 是two policeman 还是two policemen?为什么