Ａ：Douzo. どうぞ。 Please (have some.)
Ｂ：Jaa, itadakimasu. じゃあ、いただきます。Well, then I’ll have some.
Gochisou sama deshita.ごちそうさまでした。Thank you (That was delicious).
20. jaa, ja じゃあ／じゃ well then, if so
21. itadakimasu いただきます ritual expression before eating
22. gochisou-sama ごちそうさま ritual expression after eating
23. gochisou-sama deshita ごちそうさまでした formal version of gochisou-sama
Ja is used to follow up on what has been said, to switch topic, etc.
Itadakimasu literally means ‘I’ll humbly accept it’ and is used before eating or receiving a gift. Gochisousama (deshita) shows gratitude for the food or drink one has been offered. Even when alone Japanese people tend to whisper itadakimasu and gochisousama to start and end eating.