Ответ:

1)This is the worst CD in my collection

2)The sea isn't warm enough to go swimming today

3)This book isn't as cheap as that one

4)The other questions are more difficult than this one

5)I'm not as good at Science as I am at Art

6)This sweater isn't big enough for me to wear it now

7)The last book I read was more interesting than this one

8)This is the most comfortable chair in the room!