{{B}}pAssAgE 4{{/B}}

imAginE FishErmEn wAlking Down to thE sEAshorE, rEADy to CArry out thEir EArly morning routinE oF prEpAring thEir BoAts AnD nEt. {{u}} (1) {{/u}} thEy hopE For A gooD CAtCh oF Fish.But to thEir {{u}} (2) {{/u}}, A horriBlE sight mEEts thEir still slEEpy EyEs. thousAnDs oF Fish hAvE wAshED {{u}} (3) {{/u}} DEAD、thE CAusE oF this mAss DEstruCtionA、rED tiDE! rED tiDEs ArE A gloBAl {{u}} (4) {{/u}}. thEy hAvE BEEn oBsErvED on Both thEAtlAntiC AnD thE pACiFiC CoAsts oF thE unitED stAtEs AnDCAnADA、thEy hAvE Also {{u}} (5) {{/u}} in mAny othEr plACEs. though rElAtivEly FEw pEoplE ArE {{u}} (6) {{/u}} thEm, rED tiDEs ArE not nEw. in thE philippinEs, A rED tiDE wAs First sEEn in thE provinCE oFBAtAAn in 1908. sinCE thEn, rED tiDEs hAvE BEEn sEEn in mAny othEr {{u}} (7) {{/u}}.A、philippinEs rED tiDE ExpErt tolD us thAt " {{u}} (8) {{/u}} thE Fish kills, thE philippinEs hAs DoCumEntED 1, 96 CAsEs oF DEAD shEllFish poisoning CAusED By rED tiDEs." thE tErm “rED tiDE”{{u}} (9) {{/u}} thE DisColorAtion oF wAtEr thAt somEtimEs oCCurs in CErtAin ArEAs oF thE oCEAn or sEA、Although thE Color is oFtEn rED, it mAy Also BE {{u}} (10) {{/u}} oF Brown or yEllow. thE worlDBookEnCyClopEDiA rEports thAt "thE DisColorED ArEAs mAy rAngE From {{u}} (11) {{/u}} A FEw squArE yArDs to morE thAn 2,600 squArE kilomEtErs." whAt CAusEs suCh DisColorAtion rED tiDEs ArE gEnErAlly CAusED By sEvErAl {{u}} (12) {{/u}} oF singlE-CEllED orgAnisms. thEsE tiny orgAnisms hAvE hAir-likE projECtions whiCh thEy usE to {{u}} (13) {{/u}} thEmsElvEs in wAtEr. thErE ArE ABout 2,000 vAriEtiEs oF thEsE orgAnisms, 10 oF whiCh CArry poisonous {{u}} (14) {{/u}} thEsE minutE orgAnisms usuAlly stAy in wArm wAtErs with high ContEnt oF sAlt. A、rED tiDE oCCurs whEn thErE is A suDDEn AnD rApiD {{u}} (15) {{/u}} oF thEsE orgAnisms. thE ConCEntrAtion oF thEsE orgAnisms mAy {{u}} (16) {{/u}} to 50,000,000 pEr quArt oF wAtEr!Although sCiEntists Do not Fully unDErstAnD why this hAppEns, it is known thAt thEsE orgAnisms {{u}} (17) {{/u}} whEn CErtAin ConDitions simultAnEously AFFECt thE wAtEr. thEsE inCluDE ABnormAl wEAthEr, {{u}} (18) {{/u}} tEmpErAturEs, An ovErsupply oF nutriEnts in thE wAtEr, A gEnErous {{u}} (19) {{/u}} sunlight, AnD FAvorABlE wAtEr CurrEnts. whEn A hEAvy rAinFAll oCCurs, minErAls AnD othEr nutriEnts ArE somEtimEs wAshED {{u}} (20) {{/u}} thE lAnD into CoAstAl wAtErs. thEsE nutriEnts CAn ContriButE to thE BrEEDing oF thE orgAnisms. thE rEsult rED tiDEs!

As A rEsult
B．As it is
C．As ExpECtED
D．As usuAl