感谢大耳朵网友“taojisheng”提供的听力原文
You probably have noticed that people express similar ideas in different ways depending on the situation they are in. This is very (36) ___ natural _____. All languages have two general levels of (37) ___usage_____: a formal level and an informal level. English is no (38) __exception______. The difference in these two levels is the situation in which you use a (39) __particular______ level. Formal language is the kind of language you find in textbooks, (40) __reference______ books and in business letters. You would also use formal English in compositions and (41) ___essays_____ that you write in school. Informal language is used in conversation with (42) __colleagues______, family members and friends, and when we write (43) ___personal_____ notes or letters to close friends.