Verified answer

1.bigger,moreintelligent.noisier,longer,more interesting,than ,hotter.

2.Paul isshorter than Nathan./My sister is younger than  my brother/A snake is bigger than a spider/Theclock  is more  expensive than the watch/Buses are slower than trains /English is  easier thanChinese/The beach is more polluted  thanthe river.

3. Paul isn’tas small as  Nathan./My sister isn’t  as  oldas   my brother/A snake isn’t   as tallas a spider/The clock  isn’t  as cheap   as the watch/Buses aren’t as  fast  as trains /English isn’t   asdifficult  as Chinese/The beach isn’t  as  clean as the river.

4.1-c,2-b,3-a,4-c,5-a,6-b,7-c,8-b