{{B}}sECtionA、ConvFrsAtions{{/B}}
{{i}} in this sECtion you will hEAr sEvErAl ConvErsAtions. listEn to thE ConvErsAtions CArEFully AnD thEn AnswEr thE quEstions’ thAt Follow.{{/i}}

{{i}} quEstions 1 to 4 ArE BAsED on thE Following ConvErsAtion.At thE EnD oF thE ConvErsAtion, you will BE givEn 20 sEConDs to AnswEr thE quEstions. now listEn to thE ConvErsAtion.{{/i}}

how DiD thE sCiEntists EstABlish thE ExistEnCE oF thE plAnEtsA．thEy stuDiED thE grAvitAtion in thE AppEArAnCE oF thE pArEnt stArs.
B．thEy wErE ABlE to sEE thE plAnEts with A tElEsCopE.
C、thEy CompArED thE pArEnt stArs to thE sun.
D．thEy sEnt AstronAuts on A mission into spACE.