Answer: the answer is unless.
Explanation:
Sternly, maybe could just be grim ( formiadable, harsh, uninviting, depressing, lack of humor, etc)
If you don’t do this 3rd grade homework yourself omg...
Churchill’s speech was meant to inspire the British people to continue fighting in the war, and to protect and fight for the survival of their empire and everything they stood for, and to do this as a united nation against their opponent.