下图是“绿叶在光下制定淀粉”实验的各个步骤示意图,请据图回答。(1)用图中编号表示实验步骤的操作顺序:____ 。(2)在该实验中,叶片的____ (填“遮光”或“未遮光”)部分是实验组,此部分用碘液染色后呈蓝色。(3)该实验的结论之一是绿叶只有在____ 下才能进行光合作用。
This is a photo of my family . I'm John . I'm ten . My sister is seven . We are in the same school .My grandparents are Americans . My father is 42 .He is a driver . My mother is 40 . She is a teacher . We are very happy .
Don't go out ___ the rain stops. Otherwise, you'll get wet!
呼吸时,氧气由肺泡进入血液的原因是( )
我国某地有一口井,一年中只有一天太阳可直射井底,该地位于( )