完形填空。 What must you do when you receive a present 1 your birthday? You have to sit down and write a thankyou note. The words 'Thank you' are 2 important. We have to use them very often. We say them when someone gives us a drink, 3 us to pick up things, lends us a book or gives us a gift. Another important word is 'please'.   Many.people 4 to use it. It is rude to ask someone to do something without saying 'please'.We have to use it when we 5 something, too. It may be a book 6 a pencil, mor rice or help.  We have to use 'please' to make the request pleasant. We have 7 'Sorry', too.  When we have 8 someone, we'll have to go up and say we're sorry.When we have forgotten something, we will also say 'sorry'.  We can make people 9 wrongs by saying it. These three words are  1 0 . Our children must learn to use them.  They are pleasing words to use in any languages. (     )1. A. in (     )2. A. so (     )3. A. helps (     )4. A. want (     )5. A. ask for (     )6. A. but (     )7. A. learn to say (     )8. A. fell (     )9. A. remember (     )10.A. difficult but important B. at B. very B. has B. forget B. say B. and B.  to learn and say B. touched B. forget B.  simple but important C. for C. rather C. lets C. like C. need C. or C.  learn and say C. felt C. need C.  useful but difficult D. to D. such D. makes D. remember D. want D. as D.  to learn to say D. hurt D. think D.  helpful but difficult