如图所示水平地面上有三个底面相同、倾角分别为30°、45°、60°的固定斜面,三

题型:选择题

问题:

如图所示水平地面上有三个底面相同、倾角分别为30°、45°、60°的固定斜面,三个斜面与物体间的动摩擦因数相同,同一物体沿三个斜面从顶端开始由静止下滑到底部的过程中,克服摩擦力做功情况正确的是(  )

A.沿倾角为30°的斜面下滑最多

B.沿倾角为45°的斜面下滑最多

C.沿倾角为60°的斜面下滑最多

D.一样多

考点:匀变速直线运动的位移与时间的关系滑动摩擦力、动摩擦因数力的合成牛顿第二定律
题型:选择题

—How ________ for one apple?  

—One yuan.[ ]

A. much        

B. many         

C. long

题型:选择题

【化学——选修5:有机化学基础】(15分)

合成生物碱类天然产物的重要步骤之一是脱水环化,某生物碱F的合成路线,如下图所示:(图中的R,R′,R″均代表烃基)

已知以下信息:

①A为芳香族化合物,只含C、H、O三种元素,1molA完全燃烧需消耗7.5molO2

②分子中含有“”结构的物质可发生下列反应:

③两个羟基连接在同一个碳原子上时极不稳定,容易脱水:

④合成路线中Ⅰ和Ⅴ反应原理相同;Ⅲ和Ⅳ均有水生成;

回答下列问题。

(1)反应Ⅴ中的R″Cl的系统命名为             ,B中官能团的名称为            

(2)下列叙述正确的是        

a.仅用新制Cu(OH)2可以鉴别A、B、C三种物质

b.D与PPA()互为同分异构体

c.E和G均可发生加成反应、水解反应

d.F的分子式为C17H17NO2

(3)某化合物结构简式为,它在一定条件下也能发生类似Ⅳ的环化反应,写出该化合物发生环化反应的化学方程式                         

(4)若H与G互为同分异构体,且H可发生消去反应,写出符合要求的H结构简式(任写一种) 

                                     

(5)根据已有知识并结合相关信息,完成以下由X和CH3MgBr为原料制备的合成路线流程图:

注:①X与B互为同分异构体,X的核磁共振氢谱有4组峰,且峰面积之比为3:2:2:1.

②无机试剂任用,有机物用结构简式表示,合成路线流程图示例如下:

题型:选择题

As soon as the manager entered his office, he began to_____the telephone book on his desk.

A.look up

B.look into

C.look upon

D.look through

题型:选择题

企业发行可转换公司债券时,收到的款项当中属于权益成份的公允价值部分应记入______

A.盈余公积
B.资本公积——资本溢价
C.资本公积——其他资本公积
D.利润分配——未分配利润

题型:选择题

Can you imagine how you would feel if you fell dangerously ill and could not reach or call a doctor Millions of people (1) the world are in this unfortunate (2) , living in distant places (3) there are no railways, no proper roads and no telephones. Thousands of (4) are lost every year (5) could have been saved if medical attention (6) in time. (7) today help could be brought quickly and easily (8) many of these people (9) full advantage was taken (10) the aeroplane. (11) country has proved this (12) than Australia. The Australians (13) greater use of the aeroplane than any (14) people in the world. In no other country (15) the total number of miles flown by the (16) person so high. In fact, it has been (17) that Australians jump into planes (18) people in other countries jump into trains and buses. It is not surprising, (19) that Australia should have been the first country (20) a Flying Doctor Service.

A.people

B.children

C.lives

D.families

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