“How long do you suppose it is _______ he left for Japan?” “No more than half a month.”

We are looking forward to ________ you as soon as possible.

Everyone here will thank the firefighters forthe things they do to prevent fires ______ the environment safer

I don’t doubt_______ he took the firstplace in his class; but I do doubt_______ he will succeed in the end.

At present, lots of people would rather ________ in the country because there is ________ pollution in the city.