Can you guess if they ______ to play basketball with us –I think they’ll come if they _____ free.

It’s time to say goodbye to my school. I’ll always remember the people ____have helped me.

The eighteenth and nineteenth centuries _____ the widespread use of electricity and the birth of the steam engine , leading to the development of factories and cities.

resident announced permission for oildrilling off the shorelines, ________ the country’s effort to reduce energyimport from foreign countries.

When I passed the river, I saw some children ______ on the sand.