某种商品若按标价的八折出售，可获利20%，若按原价出售可获利(     )

如图所示，将绿色植物放在暗处一昼夜后，选取一片叶片用不透明的锡箔纸遮盖一部分，放置在阳光下照射几个小时后，取下叶片，去掉锡箔纸，经脱色、漂洗再用碘液处理，结果发现，遮光部分不变蓝色，曝光部分变蓝色．本实验说明：（　　）

①光合作用需要光         ②光合作用需要二氧化碳

③光合作用需要叶绿体   ④光合作用放出氧气

⑤光合作用制造淀粉      ⑥光合作用需要水分．

Do you often watch TV? Maybe your 1 is "Yes". Most children like watching TV 2it's interesting and relaxing. They can also learn a lot and know3 things about their country and the world. TV helps to open children's eyes. TV can open 4mind. They can learn some better ways of 5 things. Many children are always6 with their studies, so they watch TV only on weekends. 7 some children watch TV every night. They go to 8very late and they can't have a good rest. I 9 it's good to do so. What do you 10 it?