— Wow! You look different! You            wear glasses.— Yes, I did. But now I am wearing contact lenses(隐形眼镜).

His shoes are muddy. He        be working in an office all day.

Jim______   sing Chinese songs very well now, but he______do it last year.

—What have you learned from your experience in Thailand?—Well, meeting people from another culture ______ be very difficult．

It’s cold here. _________ I switch on the heating?