Meaning: back to the planning stage. Start again on a new design or plan after the failure of an earlier attempt

Examples Sentences:
1.- My experiment was a failure, so I’m back to the drawing board.
2.- Sometimes the best way to proceed after a mistake is to start over and go back to the drawing board.

Meaning: to be an important and successful individual. To be an influential person.

Example Sentences:
1.- The guy is among the big cheeses in the region and his word rules.
2.- I am not the big cheese and understand why you went to him to get your work done.

Meaning: to wait for the perfect moment to do something. To kill time while the most opportune moment arrives.

Example Sentences:
1.- The big tiger bides time until the zebra had to make its way to the water fountain and then struck.
2.- He is just biding time until the death sentence is executed.

Meaning: to be certain about something’s validity. To be true or legitimate. To be (something) without any doubt about it.

Example Sentences:
1.- The government has clarified beyond a shadow of doubt that the people who have been evading taxes so far will be caught very soon.
2.- I knew beyond a shadow of doubt that he will not keep his word. That is why I did not lend him a single penny for his business.