①写出 a、b仪器的名称：a____，b____．

②实验室采用高锰酸钾制取氧气，应选用的发生装置是____（填编号），试管口要放一团棉花，其作用是____．该反应的文字表达式是____，基本反应类型是____．

③采用过氧化氢制取氧气，如需随时控制生成气体的量并节约药品，发生装置最好选用____（填编号），如用D装置收集氧气，检验氧气是否收集满的方法是____．

④装置F用排空气法收集氧气，则气体应从____（填“a”或“b”）端通入；装置F用排水法收集氧气，先将瓶中装满水，再将气体从____端通入．

⑤实验室常用无水醋酸钠和碱石灰的混合固体在加热条件下制取甲烷气体，发生装置可选择____（填序号）．甲烷气体一般采用装置E进行收集，收集满后集气瓶的放置方式如图G所示，据此可推断甲烷一定具备的物理性质是：____、____．

⑥装置的气密性是保证气体实验成功的关键，下列图示操作中，不能用于检查气密性的是____

B

    I have a twin brother, Bob. He is taller than me. His hair is shorter than mine. Many people think we must have many things in common. But in fact this is not true. Bob is more outgoing than me. When my parents' friends come to our house, Bob often sits there and talks to them. But I often sit there and say nothing. Bob likes reading, cooking and drawing. I just like swimming and playing basketball. He has more hobbies than me, but he is not as athletic(擅长运动的) as me. Because Bob does better than me at school, my mom often says to me, “Bob is younger than you, but he can get better grades, you should learn from him.” We both like eating fast food and listening to music.