Ответ:

1/Ann's eyes are as brown as John's eyes.

2.Cathy is not as tall as Rose.

3.Linda's hair is as curly as Mary's.

4.Bill is as a good pupil as Tom

5. Your grandparents are not as old as mine.

6.Lisa is not as good at skating as Brenda.

В первом не уверена, т.к. в предложении нет прилагательного, нужного для этой конструкции, поэтому поставила просто brown