看一看，选一选。

(     ) l. This ruler is short. That one is shorter.

(     ) 2.  He is tall.  His friend is taller than him.

(     ) 3. She is thin. Her sister is thinner.

(     ) 4.  He is fat.  His brother is fatter.

(     ) 5. This apple is big.  That one is bigger.

(     ) 6. This ball is small. That one is smaller.