Although the painting is very ____ pleasant, it is thought to be copied with a modern printing machine．

It is the prevention of disease_____ its successful treatment that has led to the rapid increase of the world’s population.

Jack has a good habit of keeping a diary every day;      he is very good at writing.

The famous professor’s lectures, though ____ informal, are considered far more informative and interesting.

Proper exercise is good for your health._____, too much is bad for it.