So we have learned in the overview about Vietnamese grammar that it has the same Subject + Verb + Object (SVO) sentence structure as English. If you haven’t gone through that lesson, it’s highly recommended you read it before proceeding with this lesson because you can find there the big picture of Vietnamese Grammar as well as the most important differences from English.
The grammar of Vietnamese nouns is plain and simple. There is no singular and plural form: pen in two pen has the same form as pen in one pen: no adding of suffix –s whatsoever.