Grammar Lesson!
"desu"････You've already learned it at Lesson 1! Remember?? "desu" means " is " or "state of being"
"ka"･･･ is a interrogative word,which always has to be put on the end of senteses
"O" using with "genki"･･･is a prefix meaning politeness.
You can use it without "O" like "genki desu ka?"
If you want to say further friendly ,you can say "genki?"
"desu" is also a group of polite words.
