lonely, lonelier, the loneliest

lucky, luckier, the luckiest

 pretty, prettier, the prettiest

既可以加er，又可以加more的有clever friendly lovely healthy calm free

clever, cleverer, the cleverest/ more clever most cleverest

 friendly, friendlier, the friendliest / more friendly, the most friendly

polite, politer, the politest （more polite，the most polite）

shy也有两种：shyer shyier