4. Bill was too stupid to understand what I had said.

⇒ Bill is not smart enough to understand what I had said.

5. This bag is too heavy for her to carry.

⇒ This bag is not light enough for her to carry.

6. The test was too difficult for them to do.

=> The test was not easy enough for them to do.

7,I'm too poor to help you with the money.

=> I'm not rich enough to help you with the money.

8, This book is too dull to read.

=> This book is not interesting enough to read.

9, The room is too dark for us to study

=> The room is not bright enough for us to study.

10, The shelf is too high for her to reach.

=> The shelf is not short enough for her to reach.