Answer:
They’ve worked their whole lives and are looking forward to retirement.
They are unemployed.
They have been unemployed most of their lives, but continue to look for work.
They’ve worked their whole lives and continue to do so.
These words give the reader a feeling of hope either for the main character or another character. It lightens the mood and stresses a more positive scenario.
Here is the answer to the given question above. Based on the given sample sentences, the best way to combine the sentences using a semicolon would be this: <span>The world’s nations must cooperate; one nation cannot solve the world’s problems by itself. The correct answer would be the second option. Hope this helps.</span>