Too strange questions I meet...It is my tragic day!

1. If paging and swapping are occuring often, what is the problem?
2. The SGA could not fit to actual memory
3. the SGA could not fit to virtual memory
4. Which in Oracle expert could only be load from .xdl or...(I forgot)
5. Instance data
6. Schema data
7. Environment data
8. database data

I meet two questions about instance data, schema data, enviroment data of Oracle expert, each one I select enviroment data. I do not know the problem. The two questions are the first two of my tuning test, so my score is 47, only one more need to pass. It is my tragic day! Please tell me about the Oracle expert.

3. If a table is for query only, and do not have update operation, what PCTFREE is good?

1. 0
2. 10
3. 50 I select a. Maybe I am wrong.
4. I meet one sentence in the test: Oracle could not take a tablespace offline unless it have a active rollback segment. I suppose this sentence is wrong. If "unless" is "if". I suppose it is right. Please tell me what is your understand. It is just test English, not