Will you go with us for an outing on Saturday?— I’d like to, but I am really busy these days. I can’t _______ a whole weekend.

A naval parade can provide a platform, _____ navies on behalf of different nations can communicate．

Taiwan is a part of China, and it’s ______ the southeast of our country. [ ]

Listen！Helen is singing in the next room.—It _____be Helen .She has gone to Beijing.

Though to see us, the professor gave us a warm welcome.