签证可以去美国了吗？
谢邀 首先，我来纠正一下题主的错误：不是visa， 是VISA. VISA是维萨信用卡公司(Visa Inc.)的注册商标，因此使用这个词来指代“签证”是错误的！ Visa 是一个国际性银行机构，其会员银行遍布全球180多个国家和地区。每个国家的旅行证件上都有visa的标志（即visa logo），但是这是给印刷者使用的，而并不是用来表示某种特定的签证类型。
在大多数国家，visa一词通常用于美国的非移民签证。但请注意：visa 不只限于非移民签证；在美国使领馆网站上列出的所有签证申请表格D和E中，都用visa或visa (无粗体或者黑体)来代替所有的签证类型的名称，包括所有非移民签证、部分移民签证以及某些其他特殊用途签证，所以这些表格中的任何 visa 一词都不是代表特定签证类型的。
在英文语境下没有一种签证被称为 a “Visa". 与visa 一词对应的是 entry permit， entrance permit， entry authorization 和 similar words for the different types of visas issued by various countries; 如： Chinese entry visa and Canadian visitor's visa 而中国人常说的 A 类B类C类等所谓的 visa category 则是由签发该签证的美国使领馆内部根据其自身的需要来划分的，这个分类方式并没有在国际上统一，所以在其他英语国家的人看来是完全没意义的，并且他们可能连 visa 这个词都不认识... 所以您以后千万别再用 visa 来表示各种签证了哈！
其次，我们来讨论一下题主问的问题 1st problem： you have not been approved yet. What is in the stamp/label on your passport？ The stamp should say "Approved" or something along those lines， right？ If it says anything else that indicates that this is still an application with pending approval status， then yes： You must wait until they approve before going to USA！
2nd problem： I don't know what kind of interview you went through， but usually if you are just applying for tourist visas at the Beijing consulate office， there won't be any questions asked during their interviews. So the only time when I got called into another room was after my fingerprint scanning process was finished where some immigration officer wanted me to write down some personal information as part of processing paperwork. But she didn't ask about China or other stuff because our passports were stamped already. Maybe it depends on the embassy branch you go to. It doesn't really mean much either way.
3rd problem： As far as i know， once they issue you a visa it will last forever provided that there wasn't any changes made in the requirements of issuing valid visas later on due to political reasons etc. Of course， everything comes up to date eventually so make sure you check periodically since sometimes travel agency can also get you stuck！ For example， we had one student