Many people think that it is ______ making such an experiment.

Although my grandfather is in his eighties, he is still as ________ as a young man and hates sitting around doing nothing all day.

My car’s performance is ___ since the engine’s been tuned and the tires have been changed．

It is ________ that I can still remember ______ was discussed at the meeting.

— Do you think the film is good?— Terrific! ______