With him ______ the way, we had little trouble finding the school.

-- Come on, please give me some ideas about the project. -- sorry, with so much work _____ my mind, I almost break down.

The factory produced many famous cars, none of _____shipped to foreign countries.

The sales _____ steadily, the factory needs an increasing supply of raw material.                                                   

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