日本語 Japanese Ask Questions Thread 6

If you have a question about the language, ask it and fellow 4channers might see it and answer it for you.

Japanese - Ask questions thread
http://dis.4chan.org/read/lang/1174719097/1-40

日語 Japanese Ask Questions Thread2 質問
http://dis.4chan.org/read/lang/1206158123/1-40

日本語 Japanese Ask Questions Thread 3
http://dis.4chan.org/read/lang/1267485093/1-40

日本語 Japanese Ask Questions Thread 4
http://dis.4chan.org/read/lang/1302350850/1-40

日本語 Japanese Ask Questions Thread 5
http://dis.4chan.org/read/lang/1330050873/1-40

I'm preparing for an oral test tomorrow and I just read a point on the marking sheet that says: "Say ‘しつれいします’ three times appropriately." which is confusing the shit out of me. Most of my tests have been straightforward grammar and dictation written tests, so I'm very poor when it comes to actual speech. This oral test is a 2 minute 'show and tell' sort of thing, so when should I be using しつれいします? As I enter the room and when I'm leaving, but when else?