下列选项中，公司不设监事会的国家是( )A．英国 B．德国 C．法国 D．意大利

碳的质量分数大于2.11%的铁碳合金称为钢。( )

根据短文内容判断句子正误，正确的在题前括号内写“T”，错误的写“F”。

Dear Tom,

      I am studying in Beijing now. I have a day off today. Now let me tell you something about Beijing. In our

country people drive cars on the left side of the road, but here in Beijing, on the right side. Many people of

London go to work by car, while most people of Beijing go to work by bike. The weather of Beijing is better

than ours. It's fine for long here, but we have so many cloudy days in London. Students here work hard at

their lessons and a lot of people can speak English. It's a pity that students in our country don't work hard

and few people know Chinese. That's all for today. Please write to me soon.

                                                                                                                                 Your ever,

                                                                                                                                    Peter

( )1. This letter is from an English boy to his friend Tom.               

( )2. Peter is a farmer, not a student.                                   

( )3. Tom may be a middle school student in London.                       

( )4. In England cars go along the road on the right side.                

( )5. Peter thinks the Chinese students work harder than English students.

某烃类化合物A的用仪器可以测出其相对分子质量为84，分子中含有碳碳双键，分子中只有一种类型的氢。

（1）现有以下的实验室仪器：

A．^１H核磁共振仪

B．质谱仪

C．红外光谱仪

D．元素分析仪请你选择分别用什么仪器。①测出相对分子质量 　   （填字母代号，下同）、

②测出官能团碳碳双键          、③测出几种类型的氢             。

（2）结合题给信息，可以判断A的结构简式为                    ；

A中的的碳原子是以什么形式杂化？                 ；

（3）在下图中，D₁、D₂互为同分异构体，E₁、E₂互为同分异构体。

反应②的化学方程式为                                                    ；

C的名称为                       ；反应类型为             ；。

E₂的结构简式是                  ；④、⑤的反应类型依次是      、     

如图是小华利用杠杆提升浸没在水中的物体B的示意图．杠杆CD可绕支点O在竖直平面内转动，OC：OD=1：2，物体A为配重，其质量为200g．烧杯的底面积为75cm²，物体B的质量为320g，它的体积为40cm³．当物体B浸没在水中时，水对杯底的压强为p₁．当用力拉物体A，将物体B提出水面一部分以后，杠杆恰好在水平位置平衡，此时，竖直向下拉物体A的力为F，水对杯底的压强为p₂．若p₁与p₂之差为40Pa，则拉力F的大小为______N．（g取10N/kg，杠杆的质量、悬挂物体A和物体B的细绳的质量均忽略不计）

在住宅智能化设计中，户内应设置紧急呼叫按钮。( )