It is natural to assume that as the Sun grows older, and uses up its hydrogen fuel--which it is now doing at the spanking rate of half a billion tons a second--it will become steadily colder and redder.

A. it is extremely important to develop tourism.
B. Building roads and hotels is essential
C. Support facilities are highly necessary
D. Planning is of great importance to tourism

A. he refuses to follow his own energy cycle
B. he is a lazy person
C. he is not sure when his energy is low
D. he is at his peak in the afternoon or evening