This document discusses using simple sentences in Japanese with just a noun and です to say something is something. It notes that sentences often lack a subject when it is clear from context, but は can introduce the subject if it is not clear. Some example sentences are provided to demonstrate this, such as "I am a student" being expressed as 学生です. It also explains that particles like は attach phrases to the sentence, with は introducing a topic, and that Japanese does not distinguish between one thing and multiple things in the way English uses "a".