DEAR ABBY: My husband and I both work, and during the dinner hour we have our first opportunity of the day to sit and talk.

We have a very dear friend who is semi-retired and works at home and lives near us. While we enjoy our friend's company, we find it not so enjoyable when our friend arrives during dinner, pulls up a chair and chats about anything and everything with no thought whatsoever as to whether or not our dinner or evening plans have been interrupted by her visit. Her visits last anywhere from 30 minutes to three hours.Our time at home is precious since we both work and must plan to fit our house and yard work into our business schedules.

We can find no way to communicate this problem to our friend without offending her since we are sure it never occurred to her that her visits are often an intrusion and sometimes spoil previous plans that we may have had - whether it be relaxation, house or yard work. We are hoping that our friend will see this letter and understand that not everyone is semi-retired with evenings free to socialize and entertain unexpected company. - BUSY FRIENDS IN NEW YORK

DEAR BUSY: I receive no fewer than 1,000 letters on a slow day, and approximately 100 of them sound exactly like yours, so let me kill one hundred birds with one stone (with apologies to the S.P.C.A.):

Nobody can impose upon you without your permission. People who make a practice of dropping in and staying anywhere from 30 minutes to three hours and spoil your previous plans can hardly be called "dear friends." And if you tolerate this kind of "intrusion" (your word), you are encouraging it.

If you can't summon the courage to tell a drop-in friend that you have plans for the evening - even if it's only to wash your hair and go to bed early - you will have to put up with the intrusion. Unless, of course, your friend reads "Dear Abby," recognizes herself and takes the hint. But don't count on it.

DEAR ABBY: I have been a telemarketer for the last 10 years, and I thank God every day for my job. I have no other skills and do not have a degree in anything. I have rheumatoid arthritis, high blood pressure and diabetes, so needless to say, I could never hold down a factory job or do waitress work.

I always read your column and usually like your answers, but you are off the wall knocking people who make a living telemarketing. I am a single parent who makes enough money to support myself and three children, and this job keeps me off welfare.

If people aren't interested in what I'm selling, all they have to do is say, "No, thank you," and hang up. I'm sorry if I call some folks at an inconvenient time, but regardless of what they say to me (and I have heard everything), I am always polite and keep my cool.

You probably won't print this, but maybe you will realize that telemarketers provide an important service, plus we provide jobs for a lot of people who otherwise might be on welfare. We hire pregnant women, students, handicapped people, overweight people and mothers with small children who can work from their homes.

Thank you, Abby, for letting me get this off my chest. - I'M OK IN OKLAHOMA CITY

DEAR ABBY: I am a 14-year-old girl and just love your column. Some of my friends and I were talking about different things, and we have a question to ask you. Can a girl get pregnant when she "does it" with a guy for the first time? - FOUR GIRLS IN CHARLESTON, W.VA.

DEAR GIRLS: The answer is YES!

C) 1989 Universal Press Syndicate