toDAy, most CountriEs in thE worlD hAvE CAnAls. mAny CountriEs hAvE Built CAnAls nEAr thE CoAst, AnD pArAllEl{{u}} (67) {{/u}}thE CoAst.EvEn in thE twEntiEth CEntury, gooDs CAn BE movED morE ChEAply By BoAt thAn By Any othEr{{u}} (68) {{/u}}oF trAnsport. thEsE{{u}} (69) {{/u}}mAkE it possiBlE For BoAts to trAvEl{{u}} (70) {{/u}}ports Along thE CoAst without BEing{{u}} (71) {{/u}}to thE DAngErs oF thE opEn. somE CAnAls, suCh As thE suEz AnD thE pAnAmA, sAvE ships wEEks oF timE By mAking thEir{{u}} (72) {{/u}}A thousAnD milEs shortEr. othEr CAnAls pErmit BoAts to rEACh CitiEs thAt ArE not{{u}} (73) {{/u}}on thE CoAst; still othEr CAnAls{{u}} (74) {{/u}}lAnDs whErE thErE is too muCh wAtEr, hElp to{{u}} (75) {{/u}}FiElDs whErE thErE is not Enough wAtEr, AnD{{u}} (76) {{/u}}wAtEr powEr For FACtoriEs AnD mills. thE sizE oF A CAnAl{{u}} (77) {{/u}}on thE kinD oF BoAts going through it. thE CAnAl must BE wiDE Enough to pErmit two oF thE lArgEst BoAts using it to{{u}} (78) {{/u}}EACh othEr EAsily. it must BE DEEp Enough to lEAvE ABout two FEEt oF wAtEr{{u}} (79) {{/u}}thE kEEl oF thE lArgEst BoAt using thE CAnAl. whEn thE plAnEt mArs wAs First{{u}} (80) {{/u}}through A tElEsCopE, pEoplE sAw thAt thE rounD Disk oF thE plAnEt wAs CrisEs-CrossED By A{{u}} (81) {{/u}}oF strAngE BluE-grEEn linEs. thEsE wErE CAllED "CAnAls"{{u}} (82) {{/u}}thEy lookED thE sAmE As CAnAls on EArth{{u}} (83) {{/u}}ArE viEwED From An AirplAnE. howEvEr, sCiEntists ArE now{{u}} (84) {{/u}}thAt thE mArtiAn phEnomEnA ArE rEAlly not CAnAls. thE photogrAphs{{u}} (85) {{/u}}From spACE-ships hAvE hElpED us to{{u}} (86) {{/u}}thE truth ABout thE mArtiAn "CAnAls".

A．wAtEr
B．wEt
C．soAk
D．irrigAtE