Articles: a/an or the

We usually eat our meals in ___ kitchen. But if we have ___ guest, we eat in ___ dining room.

William wrote ___ letter to his bank yesterday, but he forgot to post it. This morning, he saw ___ letter on the kitchen table.

I've got ___ idea. Let's go to ___ new Greek restaurant in the Main Street tonight.

Bangkok is ___ capital of Thailand. It's ___ large city with about 8 million inhabitants.

Martin lives in ___ big town in the middle of Germany. He's got ___ dog and he'd like to take ___ dog for long walks.

When Eva White was younger, she wanted to be ___ musician. Now many people think she's the best trumpet player in ___ world.