A landing on Mars is within the _____ of current physical theory.

Sir, you are not allowed to enter the building unless you get our manager’s__.

Due to the violent nuclear leakage, the _____ of the electricity supplies put Japan’s northeastern cities in a sate of chaos.

. After so many days on the way, even Charles cheered up at the _____ of the food.

 You are _________ to have such a good teacher.