DirECtions: thErE ArE 10 BlAnks in thE Following pAssAgE. For EACh numBErED BlAnk, thErE ArE Four ChoiCEs mArkEDA,B,C、AnDD、ChoosE thE BEst onE AnD mArk your AnswEr on thEAnswEr shEEt with A singlE linE through thE CEntEr.

our plAnEt is likE A Bit spACEship. our AtmosphErE ACts {{u}} (51) {{/u}} A shiElD AgAinst hArmFul rADiAtion AnD spACE DEBris. {{u}} (52) {{/u}} holDs thE Air AnD pEoplE on thE spACEship, {{u}} (53) {{/u}} EvErything DoEsn’t FloAt AwAy.EACh oF us is An AstronAut AnD our spACEship, thE EArth, proviDEs our FooD AnD wAtEr. thE sun is our EnErgy {{u}} (54) {{/u}} AnD without it wE woulD not BE ABlE to survivE. {{u}} (55) {{/u}} EvEry spACEship, thE EArth is A ClosED systEm. thE only thing wE rECEivE From thE outsiDE is EnErgy From thE sun.EvErything ElsE must BE usED {{u}} (56) {{/u}} AgAin. wE AstronAuts Don’t sEEm to rEAlizE thAt this spACEship is thE {{u}} (57) {{/u}} onE wE’vE got. wE {{u}} (58) {{/u}} its rEsourCEs AnD wAstE thE EnErgy thE plAnts hAvE storED From thE sun. iF wE {{u}} (59) {{/u}} our spACEship, wE will DEstroy oursElvEs As wEll. mAyBE iF wE look At thE univErsE whiCh surrounDs us, wE will ApprECiAtE our own spACEship morE AnD tAkE {{u}} (60) {{/u}} CArE oF it.

A．gooD
B．wEll
C．BEttEr
D．morE