绘图题：画出冷凝式氢气干燥器的结构图。

Bob was a gardener and he had no work for a few months. One day he went out to look for a job. While he was walking in the street, he saw a poster at the gate of a big restaurant. It said the restaurant needed to hire（雇佣） a man who could grow flowers and trees well. Bob was so pleased that he went straight to answer it. There Bob was told to go back and get his old working clothes to the office. Bob did so.

The boss looked over his working clothes carefully and then decided to let Bob have the job. Bob asked the boss why his working clothes were so important. The boss answered with a smile, "Oh, young man, your working clothes are all with patches(补丁) on the knees. You know, I have dismissed（解雇） two men these days. They had working clothes with patches on the buttocks(臀部). They were too lazy."

小题1:When the boss saw Bob, he ________.

A．gave him the job at once

B．liked Bob at once

C．asked Bob to go home to get his working clothes

D．liked Bob's clothes小题2:Bob's new job was________.

A．to wash dishes

B．to clean the restaurant

C．to cook dishes

D．to grow flowers and trees小题3:We may learn that the boss was ________.

A．very clever

B．foolish

C．very kind

D．hardworking

商业汇票上的出票人签章，为该出票人单位的（）

A、财务专用章和法定代表人或其授权的代理人签名或者盖章

B、汇票专用章和法定代表人或其授权的代理人签名或者盖章

C、公章和法定代表人或其授权的代理人签名或者盖章

D、结算专用章和法定代表人或其授权的代理人签名或者盖章

如下图所示，在半径R＝20cm、质量M＝168kg的均匀铜球中，挖去一球形空穴，空穴的半径为要，并且跟铜球相切，在铜球外有一质量m＝1kg、体积可忽略不计的小球，这个小球位于连接铜球球心跟空穴中心的直线上，并且在空穴一边，两球心相距是d＝2m，试求它们之间的相互吸引力．                         

探究活动一：在室温条件下进行如图所示实验。已知：试管内的镁条和铁片表面均被打磨洁净，且形状、大小均相同；同时加入两支试管中的稀盐酸的质量和质量分数均相等。

① 该实验的目的是   ⑻    、  ⑼      。

两支长颈漏斗中产生的现象的不同之处是   

   ⑽        。

② 若实验所用的金属均过量，则甲装置中产生的H₂ 比乙装置中产生的H₂质量    ⑾     （填“多”、“少”或“一样多”）。

探究活动二：为除去铜屑中混有的少量铁屑，并测定该混合物中铁的质量分数，现有如下A、B两组实验方案。

A：称取一定质量的样品，加入足量的稀盐酸，搅拌、过滤、洗涤、干燥、称量所得固体质量。

B：称取一定质量的样品，加入一定量的硫酸铜溶液，搅拌、 过滤、洗涤、干燥、称量所得固体质量。

③ 两种方案，你认为不能达到目的是  ⑿ （填“A”或“B”），理由是  ⒀     。

④ 在你所选取的方案中，若采用加热烘干的方式干燥滤渣，会导致测定的铁的质量分数  ⒁   （填“偏大”、“偏小”、“不变”或“无法判断”）。

由于静电（）很高，其放电火花的能量可引起易燃物着火爆炸。

A、电流

B、电位

C、电量

D、电荷