1.Her new house is smaller than her old one
2.Peter is the tallest in my class
3.The white dress is cheaper than the black one
4.According to me,Maths are more difficult than Eglish
5.Mary is the most intelligent in my group

6.The Nile is the longest river in the world 
7.No mountains in the world is higher than Mount Everest
8.She is the most pretty girl I have ever met
9.The more work he much,The more tired he feels
10.That computer works worse than this one
 

11.The bigger aparment is,the highest rent is
12.The sooner we set off ,The sooner we willc arrive
13.The better the joke is,The louder laughter is
14.The fatter she does,The more tired she feels
15.The older he gets ,The less he want to travel