--- The report is difficult to write. --- You can surf the internet, where you can find _____ information and useful expressions.
19. It’s quite an informal gathering ; you needn’t ______for it .
18. I’m surprised that you should have been fooled by such a(an) ____trick.
17. It’s known that taking exercise______your health.
16. He gave a ________smile.
15. They gave a banqnet( 宴会)_____the guests from Britain.