The exam was going fine before I received this unexpected task. “I smelled a rat” I thought.
Note: This idiom uses as personal attitude. We can’t use phrase “It smelled a rat”.
But there is a book which title is also appropriate.
go to the dogs = become run-down
The stock market fell. It’s awful! Everything is going to the dogs!!!
fishy = strange and suspicious
This man looks like an honest person but look at his biography. He was in prison many times. And his behavior at yesterday’s party was fishy.
take the bull by the horns = take decisive action in a difficult situation.
They have been trying to keep their relationship many years and finally Susan took the bull by the horns and suggested divorce.