IMAGINE THAT you have a committee to help you accomplish some task. A few people are on it just for show, and others, of whom you expected much, have proved unreliable.

However, there is one person on whom you can always count, who is consistently helpful, cheerful and, unlike the others, troubles you for a minimum of expenses. You are delighted to see this person every day, and often extend invitations to lunch or breakfast or perhaps tea, at which you enjoy making a special fuss. It is only when it comes to big, important, formal dinners that you have some qualms. There you prefer to have your showy people, and either exclude the good soul, or try to improve on his or her appearance, or arrange at least that the spouse of this person doesn't have to be there.

Isn't this shabby? Did you ever hear of anything so ungrateful and plain mean? But that, Miss Manners is obliged to tell you, is the way you are supposed to treat bread and butter.

We all know that there is no better food on this earth than good bread and butter. It delights your nostrils, appeases your hunger and keeps you company in restaurants while fancier types keep you waiting. It is always able to make itself ready for you on short notice, and is careful not to abuse your budget. No better companion can be found for breakfast, Luncheon, tea or between meals.

And yet you are not supposed to have this faithful friend at your best dinner parties. Miss Manners would hardly blame you if you haughtily declared that you would follow no such rule that insults your most loyal daily companion.

If, however, you are one of those who is willing to compromise between fashion and frienship, Miss Manners will tell you how to do it.

That happy couple, bread and butter, must be separated at the dinner table and their happy home, the bread and butter plate, razed. Butter is never directly invited to the formal dinner table, although it sometimes slithers in, having cozied up to the asparagus in the kitchen.

The bereft bread may, if it meets a more chic partner, such as caviar or anchovy sauce, appear for the canape course. If it is willing to be toasted and cut into bits, it may show up on the heels of the soup. The bolder ones just walk in, naked and dry, at this time. Tiny slices may sometimes slip onto the fish platter if they hide under tomato or cucumber slices. During the cheese course, a time at which the guests are on their third or fourth wine and not paying careful attention, it may stride in, in the form of biscuits,: and sometimes it even sneeks the butter in with it.

And what, one cries, about croissants? English muffins? Hot cross buns? Fresh-baked French, Italian or your-own-oven loaves? Garlic bread? What about sweet cream butter that has been curled into a delicate pattern or pressed into great luscious shapes?

Are these to be banised in favor of costly, complicated and often less satisfying dishes?

Certainly not. Bring all your thick slices of hot fresh bread to breakfast, swimming in gently melting butter. Bring out their favorite little plates and butter knives at luncheon, for the prettiest rolls and most cunning curlicues of butter. Decorate your tea table with elegantly thin and crustless slices of buttered bread. Enrich your family suppers with the most dashing garlic-smothered loaves.

Just make sure to shove them all ruthlessly out of the way when you want to impress your dinner guests. MISS MANNERS RESPONDS

Q: -- In view of the present international crisis, we are thinking of asking an Iranian student to stay with us. However, I'm unsure about what to serve. I know that some Roman Catholics don't eat fish on Friday and most Jews won't eat pork. Do you know if Moslems have any food prohibitions? Would a Moslem guest become upset if I didn't serve cake because we are all on low-sodium, low-calorie diets?

A: Most Moslems do not eat pork or pork products. Many Moslems do not take alcohol. No Moslems are required to eat cake. No Roman Catholics are forbitten to eat fish. Most Etiquette columnists prefer not to partake of political hot potatoes.

Q: My Husband recently gave me a strand of pearls, matinee length, and I also have a strand in the shortie, choker style. My question: When are pearls appropriate? I tend to wear them only in the evening, but it seems a shame to leave them in my jewel box so much of the time. May I wear them to the office with, say, a silk blouse and wool suit or velvet blazer?

A: Certainly. Pearls and almost always appropraite, which is the endearing thing about pearls. They adore being worn and are said to react, in gratitude for this attention, by picking up the skin tones of their owner. For this reason, many rich women wear their best pearls tucked into their nightgowns. It would be easier for Miss Manners to tell you when pearls are not appropriate, than when they are. Never wear pearls with your bathing suit.

Q: My husband, who is in all other respects a gentleman and a scholar, is extremely incorrect in one particular. When we give an occasional dinner party (maximum of three guests), he always sits down and serves himself and begins eating, sometimes even before the other guests have been alerted to the fact that dinner is ready. There is almost always enough food to go around, and it's not that good anyway, so I can't understand this behavior. I tell him the guests should be served (or be allowed to serve themselves) first and then we should all begin eating together, but he says this is oldfashioned and silly, and it's every man for himself these days.

A: Your husband's justification is the second worst explanation Miss Manners has ever heard for the rudeness of eating before one's guests. The worst was from a gentleman of Miss Manner's acquaintance who explained the fact that his wife had eaten her dessert in the kitchen before giving the guests theirs by saying, "She doesn't believe in delayed gratification."

If you can convince your husband to reverse his barbaric practice, do so. If not, allow Miss Manners to suggest to you a better excuse. As he begins eating, say to your guests, "Waite a minute, please. Elwood always likes to make sure the seasoning is just right before he lets our guests have this dish." As your meals are "not that good anyway," this will be a convincing explanation.

Q: I don't know about artifical limbs, but for some time after I was shot in the neck in World War II, I had to shake hands left-handed. One day, someone extended his left hand to mine and this felt much more natural than the upside-down right hands that everyone else had been giving me. Since then, whenever I have been offered a left-handed shake, I have shaken with my left hand. Several people have commented that this was more pleasant and natural for them, too. If you agree -- and I'm sure you do -- that the purpose of good manners is to make things as pleasant and easy as possible for all concerned, I'm sure you will modify your dictim "that you always shake hands with your right hand." y

A: You are quite right, and Miss Manners never meant to suggest that right-handed shaking was something everyone must do, able or not. Offering the left hand is a thoughtful gesture to to someone unable to shake with the right hand. The only problem is that most people are not quick-witted -- or quick-handed -- enough to make this adjustment. The disabled person therefore usually undertakes the courtesy of adjusting to the gesture.

Q: Do you think it is right for a person who doesn't live in a certain city, take New York, to criticize it? Do you think a non-New Yorker who has visited but not lived there should call it names?

A: Certainly. Criticizing New York is national Pastime. However, Miss Manners does think that the cities that serve the country as objects of hilarity, the ones whose mere names get laughts (Cleveland, Kalamazoo, Dubuque) ought to be rotated.

Q: Recently, while visiting the city of Philadelphia, my companion and I had the occasion to join some mutual friends for dinner. As we were unfamiliar with the local cuisine, we had asked our friends to choose a restaurant, assuming they would remember that we were on a tight budget. The prices on the menu were quite a bit higher than we had expected, but we carefully chose the less expensive entrees. Our friends selected more lavish main courses and added expensive a la carte salads and desserts. When the check arrived, one of our friends said, "I guess we can just split this four ways; I think that's now it's being done." We were, of course, shocked, but didn't want to create a scene over a few dollars, and so put in our 25 percent each.

Is this really the way it's being done" in the City of Brotherly Love? Should we have objected at the time of payment? Must agreements be made in advance over the settlement of dinner checks? When I buy dinner for my friends, I would like to have some way of knowing in advance that I am about to do so.

A. Brotherly love is, indeed, better served by making agreements in advance about who pays for what, and not only in Philadelphia, as Philadelphia is not the only place where prices are higher than one had expected. It is not necessary to voice objections to one's friends; one need only instruct the waiter, "Separate checks, please," at the time of ordering. Otherwise, there is the unpleasant task of asking "who had the extra rum collins?" at the end of the meal, which is probably what your friends were trying to avoid, rather than the paying of their debts.