The robot can help me sweep the floor. smart invention it is!

There are fifty _ in our school. They are all friendly to us.

— We expected you yesterday.—— I’m sorry, I______you to say that I couldn’t be here until today.

212. We must make sure that all the boxesshould__________the owners’ names.

Many strange new means of transport have been developed in our century, the strangest of _______ being perhaps the hovercraft(气垫船).