Lifeonlandprobablybeganabout430millionyearsagothoughithasexistedinthewaterforperhapsasmuchas3000millionyears.Whenwethinkofthefirstthingonlandweprobablythinkofstrangeanimalscomingoutoftheoceansbutinfactnoanimalscouldhavebeenlivingifplantshadnotbeenonlandfirst.Plantshadtobeonlandbeforeanimalsarrived.Theysuppliedthefirstlandanimalswiththesurroundingandfoodnecessitysincetheytheplantsaretheonlyformoflifethatisabletogetandstoreenergy.
Thefirstplantstoexistoutofthewaterwereprobablycertainkindsofalgae（海藻）whichwerefollowedbyotherplantsthatgrewclosetothegroundandneededwaterinwhichtoreproduce.Oncethemovetolandhadbeenmadehoweverevolution（进化）tookplacequickly.Bytheendof100millionyearsplantshaddevelopedtheirroots（根）andsomehadgottree-likeformssinceheightwasveryimportantingainingsunlight.About300millionyearsagomuchoftheworldwascoveredwithforestsofhugetrees.Inmostwaystheywerelikemoderntrees.Theyhadrootsleaveswoodbutmostlytheyhadnotdevelopedseeds.
Themainideaofthefirstparagraphis________.
A.lifeonlandprobablybegan430yearsago
B.thefirstanimalonlandcamefromoceans
C.therewouldn'tbeanimalswithoutplants
D.plantsaretheonlyformoflifethatisabletogetandstoreenergy
Whichofthefollowingstatementsistrueaccordingtothepassage?
A.Algaehasexistedformorethan430millionyears.
B.Itisimpossiblethatalgaemightbetheearliestplantonland.
C.Plantsgetfoodfromanimalsintheoceans.
D.Evolutionbeganafteranimalsappearedonland.
Plantswithrootsappearedabout________millionyearsago.
A.430 B.300 C.330 D.100
Accordingtothepassage________appearedearlierthan________.
A.apples;orangesB.oranges;apples
C.oranges;roses D.algae;wheat
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