是a USA Stamp 还是an USA Stamp（一张美国邮票）,正确呢?

是a USA Stamp 还是an USA Stamp（一张美国邮票）,正确呢? usa加a还是an是a usa 还是an usa usa加a还是ana usa还是an usa 美国到底是US还是USA呀?怎么什么地方都写US呢?麻烦详解 用US还是USA表示美国? 英语三道选择题存在疑惑.1 The Indians used to live in ___is now part of the USA.A where B which C what D that 为什么B不选?2 I haven't seen _______ this since I collected stamps.A as old as a stamp as B so an old stamp asC stamp as old 是the USA 还是USA呢?是the US 还是US 我见过the United States 的说法,但是我的英语老师又说USA前要加the,而US不用加the. 是in the USA,还是in USA? 是what the students in the USA differ from us is that还是wherethe students in the USA differ from us is that,理由 this is -------------- stamp.its ---------american stamp.A.a,the B.the,an C.an,a D.a,an usa和us是同一个国家吗? 英文单词MIT加a还是加an Could you give me____8-jiao stamp?______ MIT professor.分别用a 还是an 英文单词MIT前面加a还是an?Could you give me____8-jiao stamp?______ MIT professor. 分别用a 还是an ? ---It's an interesting game.---- Why not ____ us?A; join B;join usA 和B 哪个正确 美国的简称US是还是USA,正确的书写形式是什么?我见到有的地方是写成“US”,有的地方写成“u.s.”, 还有“U.S.A.”,到底什么地方该怎么用呢? 是a还是an stamp可数还是不可数 英语翻译是 tips for going on an educational exchange to the USA还是 tips for going to the USA for educational exchange还是 tips for educational exchange in the USA哪个好,有没错