案例分析题We are interested in the weather because it （21）us so directly—what we wear，（22）we do，and even how we feel.Geographers，however，are （23）interested in climate than in weather.Climate is the pattern of all the weather conditions over a long period of time.Generally （24），climate （25）to these normal weather conditions，not （26）daily or yearly changes.
Climate，like weather，changes （27）time.It is true （28）these changes （29）a long time，but not as long as we might expect.Records show that over the centuries large portions of the earth have experienced great changes （30）climate. 21.（）