People who speak English as a second language very well, in my experience, make fewer grammatical errors than native English speakers like myself. This is because they've taken the time to learn the correct grammar rules, and are also careful to apply these rules in speaking.
This was a problem for me when I took the GMAT exam, because there is a grammar section there that's based on some formal grammar rules that I wasn't aware of. For example, look at the example sentences for Rule #5 at the end of this article: both sentences sound correct to my ear: http://www.knewton.com/blog/gmat/2011/06/14/what-to-memorize...
This was a problem for me when I took the GMAT exam, because there is a grammar section there that's based on some formal grammar rules that I wasn't aware of. For example, look at the example sentences for Rule #5 at the end of this article: both sentences sound correct to my ear: http://www.knewton.com/blog/gmat/2011/06/14/what-to-memorize...