1.

bright, brighter, the brightest
close, closer, the closest
big, bigger, the biggest
easy, easier, the easiest
important, more important, the most important
good, better, the best
bad, worse, the worst
far, farther, the farthest

2.

the most popular
more modern than, the most modern
brighter
the largest, it is larger
best

3.

1, astronomy
2, bright
3, sky
4, telescope
5, galaxy
6, Earth
7, moon
8, solar
9, systems

4.

difficult, more difficult, the most difficult
lucky, luckier, the luckiest
young, younger, the youngest
bad, worse, the worst
useful, more useful, the most useful
bright, brighter, the brightest