proper expressions in these situatioins

[gxiang]

i am a little confused when asked to provide proper responses towards the following 3 situations. can you help me? if you are a native speaker, i'll show special thanks to you

oh, first you need to pretend that you are involved in the situation.

1.You are the director of a computer lab and have been working with an assistant, Joan, for two years. Joan has a duty to delete trash files in the computer every day. Today you wanted to install software into the computer. However, you found out that the trash files took too much space. It seems that Joan has not deleted trash files for several days. You ask Joan to delete them immediately.

2.You need to buy a new telephone card. But the store is quite far from where you live. You just got to know Miss Norris the day before yesterday, and you know she has a bike. You went to borrow the bike from her. what will you say?

3.You are revising your thesis, which is due in two weeks. You need five articles recently published on your topic, The Computer of the 21st Century. Although the library on campus does not have them, the library can ask other libraries in other states to send you the copies, which usually takes you one month to receive them. Since these five papers are very important and will add much weight to your thesis, you go to the head of Book Management Office (Miss. Anderson) to ask her to get these five articles in one week.

it seems that they are arranged from most informal to formal. what will a native speaker say in these situation? there may be more than one way of response.