1) I can see you because you are a) microscopic b) macroscopic 2) Which is NOT an element? a) oxygen (O) b) silicon (Si) c) carbon (C) d) water (H2O) 3) Oxygen is made of oxygen atoms. a) True b) False. 4) Water is made of water atoms. a) True b) False

5th Video B

由
打印
嵌入

排行榜

视觉风格

选项

切换模板

恢复自动保存：？