We must do as much as we can _______ our country richer and more beautiful. [ ]

all theproblems,_______is so difficult as this one

You have a nice watch. — Thank you. I _______ it since two years ago.

As we all know ,Columbus America and Edison light bulbs.

, you seem to be a little absent-minded. What’swrong—Oh, sorry. Actually, Iofthe family party this weekend. I have to make a list of what needs to bebought.