sick as a dog: very sick 病得十分嚴重
I was sick as a dog after that meal last night. I don't think the meat was cooked properly.
I had to go to the doctor on Monday because I was as sick as a dog all weekend.
Sally was as sick as a dog and couldn't go to the party.

go to the dogs: become bad 每況愈下
Our city used to be nice, but it's really gone to the dogs.
Boy, this party has really gone to the dogs. First, there was the issue with the caterer, and now half the guests aren't coming.
Many people think this country』s going to the dogs.

top dog: the most successful or important person 優勝者;成功者;領軍人物
My brother is the boss of his company- he is the top dog!
When I was the top dog of the business, I used to charge the most outrageous things to the company credit card.
You'll only get a truthful answer if you manage to talk to one of the top dogs.