Here are the completed sentences:

1. The weather is fine. Mary and her little brother can go to school.
The weather is **good enough** for Mary and her little brother to go to school.

2. The sun is not warm. We can’t live on it.
The sun is **not warm enough** for us to live on it.

3. The water is quite warm. I can drink it.
The water is **warm enough** for me to drink.

4. The weather is so bad that we can’t go out.
The weather is **too bad** for us to go out.

5. The film was so boring that we couldn’t go on seeing it.
The film was **too boring** for us to go on seeing it.

6. He was so old that he couldn’t run fast.
He was **too old** to run fast.

7. You speak so fast that I can’t catch up with your words.
You speak **too fast** for me to catch up with your words.

8. It is so early that we can’t go out.
It is **too early** for us to go out.

9. The film was very boring. We left before the end.
The film was **too boring** for us to leave before the end.

10. The water is so hot that I can’t drink it.
The water is **too hot** for me to drink.