Here are the completed sentences to convey similar meanings:

1. No one took care of the pets while we were in the eye of the storm.
**No one looked after them.**

2. The forest fire was so big that its smoke could be seen from space.
**It was such a big fire that its smoke could be seen from space.**

3. It's a good idea to read guidelines for evacuation carefully.
**You should read the guidelines for evacuation carefully.**

4. If James doesn’t bring a compass, he will get lost in the jungle.
**Unless James brings a compass, he will get lost in the jungle.**

5. How long is it since you last saw a storm?
**When did you last see a storm?**

6. It was raining heavily but Kathy still decided to go to school.
**Although it was raining heavily, Kathy still decided to go to school.**

7. No other tsunami in the 20th century was as high as Lituya Bay megatsunami.
**Lituya Bay megatsunami was the highest tsunami in the 20th century.**

8. Due to the heavy rains on the hills, water in the lake started to rise.
**As it rained heavily on the hills, water in the lake started to rise.**