把a、b、c、d四块金属浸泡在稀H2SO4中,用导线两两相连,可组成各种原电池.

题型:选择题

问题:

把a、b、c、d四块金属浸泡在稀H2SO4中,用导线两两相连,可组成各种原电池.若把a、b连接时,a为负极;若把c、d连接时,在d上冒气泡;当把a、c相连时,a溶解;当把b、d相连时,b为正极.则a、b、c、d的活动性顺序由大到小是(  )

A.a、b、c、d

B.a、c、d、b

C.c、a、b、d

D.b、d、c、a

考点:原电池原理电解池原理
题型:选择题

时间怀有一种公平的道义,对他所拿去的,他会给我们别的补偿。他夺去了我们肢体和精神的灵活,却给予我们宁静和安详。对这段话正确理解的一项是( )。

A.耽误的时间可以得到补偿

B.无所谓浪费时间

C.不具有灵活肢体和精神的人能获得安宁

D.晚年的宁静可以使青春活力的消失得到补偿

题型:选择题

根据短文内容选择正确答案。    

                                                       No More Chores, Please!

     Sam hated doing chores. And he had many chores. For example, on Mondays, Wednesdays

and Fridays he took out the trash. And on the weekend he always washed his father's car. He also

cleaned his own room once a week. What a chore that was ! Sometimes he even had to look after

his little sister and brother.

     Sam had a foreign friend at school. His name was Kumar. Doing chores in Kumar's family was

very different. In the house only the girls did chores. His sisters made all the beds and cleaned all the

rooms too, even his bedroom. His mother always cooked the meals, and his sisters helped her mother.

So when Kumar talked to his friend Sam about chores, he felt very lucky. One day, Sam had an idea.

He asked Kumar,"Could I borrow your sisters?" He wanted them to help him clean his room, but

they refused. Instead, they asked Sam to teach their brother how to do chores, so he could make his

own bed.

     Sam and Kumar are very good at science. They are going to be scientists after university. They

want to make a robot to do the chores. Then everyone-mothers and father, sons and daugters will

be happy!

( )1. A. Sam liked doing chores.

            B. Sam did chores only on the weekend.

            C. Sam really didn't like doing chores.

( )2. A. Sam cleaned his room once a month.

            B. Sam washed the car every weekend.

            C. Sam never looked after his brother and sister. 

( )3. A. Everyone did chores in Kumar's famliy.

            B. Kumar did some chores.

            C. Kumar's sister made his bed. 

( )4. A. Sam wanted to borrow Kumar's sister.

            B. The siste agreed to help Sam.

            C. The sister didn't want Kumar to do chores at home.  

( )5. A. Sam and Kumar plan to make a robot.

            B. They aren't going to be scientists university.

            C. No one will be happy to have a chore robot.

题型:选择题

以下哪个关于关键链的说法是正确的?()

A.关键链是关键路径的另一个名称

B.关键链是次关键路径的另一个名称

C.关键链表示的是一系列活动之间的硬逻辑关系

D.关键链是资源约束下的关键路径

题型:选择题

如果交流电压变送器输出直流电流相对于输入信号的线性误差大于允许误差时,一般通过改变线性补偿回路中的电阻来进行调整。

题型:选择题

金融IC卡相关交易中不能做撤销的交易是()。

A.芯片可读的预约换卡交易

B.芯片不可读的预约换卡交易

C.芯片可读的注销交易

D.芯片不可读的注销交易

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