—There has been less and less pollution in Leshan these years.
—The government has made a great effort on it. I’m sure this problem ______ one day in the future.
was solved
solves
will be solved
Now telephones are very popular and they are much ______ than before.
_______ it got dark, they worked hard there.
Listen up, everyone! I have ______ to tell you.
It’s ________ to leave a child alone.
I’ll return the book to the library as soon as I________it .