Imagine you are writing your term paper. You've just received a very useful reference book as a gift from Professor Smith. You meet him and express your thanks. Read aloud the following dialogue with your partner by putting in the missing words. You:Good morning, Prof. Smith. 1 ____________ for the book you sent me. It is 2 ____________ to my term paper. Smith: 3 _______________ it is helpful to you. You: Yes, it's indeed a very good reference book. I don't know how I shall express 4 __________. Smith: It's 5 ____________________. You: And I'm 6 ___________ for all the help and encouragement you've given me. Smith: I'm happy to be 7 _____________. Please don't hesitate to let me know whenever you need me. You: I will, Professor Smith. You are so 8 ________.