EI NIno is name given to the masterious andoften unpredictable change in the climate of theworld.This strange ___1_____happens every five toeight years.It starts in the PAacific Ocean and is thought to be caused by a failure in the tradewinds(信风)，which affects the ocean currents driven by these winds. As the trade windslessen in ____2____,the ocean comperatures rise causing the Peru current flowing in formthe east to warm up by as much as 5`C.

　　The warming of the ocean has far-reaching effects.The hot,humid(潮湿的)air over the oceancauses severe ___3___thunderstorms.The rainfall is increased acrossAounth American____4____floods to Peru.In the West pacific,there are droughts affecting Australia andIndonesia.So while some parts of the world perpare for heavy rains and floods,other parts facedrought,poor crops and____5____.

　　EI Nino usually lasts for about 18 months The 1982-83 EI Nino brough themost___6____weather in mordern history .Its effect was worldwide and it left more than 2,000people dead and caused over eight billion pounds ____7___of damage.The 1990 EI Nino will____9___,but they are still not __10___sure what leads to it or what affects how strong it willbe.

　　A)estimate

　　B)strength

　　C)deliberately

　　D)notify

　　E)tropical

　　F)phenomenon

　　G)stable

　　H)attraction

　　I)completely

　　J)destructive

　　K)starvation

　　L)bringing

　　M)exhaustion

　　N)worth

　　O)strike

　　答案解析：

　　1. P phenomenon

　　2. B strength

　　3. E tropical

　　4. L bringing

　　5. K starvation

　　6. J destructive

　　7. N worth

　　8. A estimate

　　9. O strike

　　10. I completely