How do you solve this problem?

He conveyed the message through the messenger.

I am studying Japanese using manga characters.

I go to the sea with my family during summer vacation.

We need to confirm his existence or nonexistence.

He got tired of doing the same job every day.

Hmm, that's a good idea.

We always swim in that bay during the summer vacation.

Masao is my best friend.

The difference between his cooking skills and mine is truly like chalk and cheese.