1.
interesting - more interesting - the most interesting;
thin - thinner - the thinnest;
cheap - cheaper - the cheapest;
easy - easier - the easiest;
bad - worse - the worst;
beautiful - more beautiful - the most beautiful;
lazy - lazier - the laziest;
far - farther (further) - the farthest (the furthest);
good - better - the best;
old - older - the oldest
2.
1) My feet are as cold as ice.
2) She looks older than her sister.
3) I think that he's Chinese.
4) Alice is much stronger than her brother.
5) Can't you eat faster than that?
3.
1) A kilogram is less than a tonne and more than a gram.
2) Jake is bad at languages, but he's not as bad as I am.
3) I get up early, at 6:30, George gets up earlier, at 6:15, and Pam is the earliest at 6:00
4) Please speak more slowly.
5) Karl is the oldest player in the team.
4.
1) What/which is the highest mountain in Europe?
2) We all play badly, but I play the worst.
3) Julie has the most interesting job in our office.
4) Your house is much nicer than ours.
5) Please walk more quickly.