Please check the sentences.

Imran   Tuesday, September 16, 2003, 16:01 GMT
I want to find out about the following sentences.

1.Would you please be kind enough to rub the chalkboard?
2.Would you please be kind enough to rub off the chalkboard?
3.Would you please be kind enough to rub it off?

I'm an English teacher and I've to use such sentences frequently.That's why you can say that I'm so fussy about them.
You may correct other mistskes, too if you notice in the text.
Clark   Tuesday, September 16, 2003, 17:06 GMT
For some reason, I think the British use "rub off," the American usage is "erase."

We would say, "would you please be kind enough to erase the chalkboard."
Wingyellow   Wednesday, September 17, 2003, 03:48 GMT
Use "clean the blackboard".
Wingyellow   Wednesday, September 17, 2003, 03:49 GMT
You DO NOT have to be that polite to order your students to clean the blackboard. Use "Clean the blackboard, please".
Clark   Wednesday, September 17, 2003, 04:55 GMT
In America, or at least the schools that I have ever attended, the teachers would clean the blackboards themselves, and if the teachers did want a student to erase it, they would use the conditional tense.
wingyellow   Wednesday, September 17, 2003, 05:16 GMT
What do you mean by conditional tense?

Teachers ask students to clean the blackboard for health reasons.
Clark   Wednesday, September 17, 2003, 06:10 GMT
The conditional tense is the "would" tense.

For example, "he would go there if he had the money." This is the conditional. One could argue that this is the subjunctive, but since English tenses are all messed up, I think that I can get away with it ;-P
Jim   Thursday, September 18, 2003, 01:45 GMT
I'd agree with Wingyellow ... no, I'd go a step further ...

You should not be so polite with your students so let's ditch the "please be kind enough to" from the very start.

I've never heard it called a "chalkboard". Though I'd have no trouble understanding you, let's change it to the more usual "blackboard".

Now your three sentences become:

1. Would you rub the blackboard?
2. Would you rub off the blackboard?
3. Would you rub it off?

Number one is not what you want. To rub something and to rub something off/out are very different things.

Number two is not quite correct either. It's not the blackboard but the writing on it that you want rubbed out.

Number three is a little inspecific. We don't use "it" without clarification. You could, however, use a gesture to give this clarification.

You could use number three and point to what you want rubbed out but it would be better still to say:

4. Would you rub this out?

You could say "rub ... off" or "erase". I like "rub ... out". Of course, there's nothing wrong with

5. Would you clean the blackboard?

The "would you" bit is still polite. You could drop it but I don't think it's overly polite. You could substitute "please" as in

6. Rub this off, please.
Imran   Thursday, September 18, 2003, 15:01 GMT
Dear jim
Thanks a lot for your advice!Please tell me where you are from.I reckon you aren't American because I've looked up the word 'chalkboard' in cambridge
international Dictionary and 'Oxford Advanced Learners' and then I discovered that this word is used in American English.I'm keen to find out your nationality
A.S.C.M.   Thursday, September 18, 2003, 23:23 GMT
Even in the U.S., "blackboard" is more common.
Jay   Thursday, September 18, 2003, 23:27 GMT
I use "chalkboard" and "blackboard" with about the same frequency, even to refer to a dry erase board. D'oh! I would say: "Please erase the board", though, and everyone would know what I meant. Though, you know, you aren't actually "erasing" the board.
Jim   Friday, September 19, 2003, 01:08 GMT

I hope I've been of some assistance. I'm from Australia.

I'd never heard the word "chalkboard" before. I suppose the Americans that I've spoken to had other things to talk about. I suppose the word makes just as much sense as "blackboard" anyway ... maybe more: blackboards are usually dark green.

Jay's got a point: if you say "Please, erase the board" or "Would you rub off the blackboard?", everyone would know what you mean ... even ESL students.

However, I'm assuming that your students aren't native speakers so I think you have to be careful about how you put things. We all know that you're not rubbing the blackboard out but these sentences seem to suggest that you are. (I suppose one of them is a question rather than a sentence.)

If I were you I'd try to avoid the confusion. Students learn from examples. "Please, erase the board" and "Would you rub off the blackboard?" are not such great examples. The blackboard is the indirect object of "rub out"/"erase"/etc. but in these examples it's in the position of the direct object.

These sentences are fully comprehensible but could hinder the students' learning of English grammar. I wouldn't get too worried about it though especially if the students are advanced enough to cope with this kind of thing.

Also I was guessing that the students that you refer to are school students. That's why I said that you shouldn't be overly polite to them. Of course, how polite you have to be depends on who your students are.

Sometimes you can have a class of people who you probably should be polite too. However, "Would you please be kind enough to ..." is extremely polite, if I had to be that polite to students, I'd rub the chalk off the board myself.
Imran   Friday, September 19, 2003, 01:56 GMT
Dear Jim
I'm so happy to read your answer that I can't tell you in words.You replied in enough detail for which I'm so thankful.It'd be very nice if you kept in touch with me because you are a native speaker I always think a boon for me.My e-mail addres is