.......We all have to learn that there are different forms of English. For example, that American and English differ and that dialects use different words and grammatical constructions........
It is also useful to bear in mind the difference between errors of faulty writing, such as typos and missing words (and readers can amuse themselves by spotting my own errors in this piece), which the spell checker may pick up and errors which arise through ignorance of grammar, spelling or vocabularly. I am thinking here of things such as lack of agreement between subject and verb.....
It's also different to note that some differences aren't necessarily a difference in grammatical construction as such. I usually see British writers (and here British speakers) write or say something like, "The government are doing whatever..." or "Tesco are having a sale on...." whereas an American would phrase it, "The government is doing whatever...." or "Tesco is having a sale on...."
The difference isn't a difference in the rules as such; both of us use is for singular and are for plural. Rather the difference apparently lies in what we consider to actually be a plural or singular noun. In the American case, we consider words such as government or Tesco to be singular because they represent a single government or a single company (both thought of as a single entity) whereas, apparently, on your side of the Atlantic they're considered plural as they represent a number of people.