Teacher:You are given a passage. You need to construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) its answer is the whole paragraph. Avoid creating questions that can be answered correctly without actually understanding the paragraph.
Teacher: Now, understand the problem? Solve this instance: Best thing you can do is set permissions on the XLS file itself by right clicking it and going to Properties and select the Security Tab (assuming you have XP).

Now you will see a few permissions listed, you can set specific permissions on the file so it can only be read and not deleted or written to etc. Or if you want remove any that says 'Everyone' and only leave yourself on the list, that why only you can open it.

Hope this helps,

Cheers!
Student:
Can any one know about Microsoft Excel ?