1b:Advantage,biogas:在第45页第二段第二句话:“farmers recycle.everyday life”
electric vehicle:第45页第三段第三句话:“They are...to run”
maglev train:第45页最后一段第四句:“it is .the air”
disadvantage biogas:.(没写.嘿嘿 上课没注意听哦~)
electric vehicle:第45页第三段第四句话:“Although ..used”
maglev train:第45页最后一段最后一句话:“however ..railways”
2 :bdca