搜题请搜索小程序“爱下问搜题”
问题 选择题

常温下，在25mL 0.1mol•L-1NaOH溶液中逐滴加入amL 0.2mol•L-1 CH3COOH溶液，有关混合溶液的判断正确的是（　　）

A．当pH=7时，一定有：c（Na+）=c（CH3COO-）=c（OH-）=c（H+）

B．当a=25时，一定有：c（CH3COO-）+c（CH3COOH）=c（Na+）

C．当c（CH3COO-）＞c（Na+）时，a一定大于12.5

D．当c（OH-）＞c（H+）时，a一定小于12.5

答案

答案：C

完形填空

Directions: Complete the following passage by using ONE word that best fits the context.

Dear boys and girls,

It’s a great honor to speak here .I’m really sorry that it will be only ten days小题1:      you graduate from our school .I have always been feeling honored to have been your English teacher in the小题2:         three years, during 小题3:I have been greatly impressed by your 小题4:  qualities such as honesty ,diligence, cleverness, unselfishness ,co-operation and so on. 小题5:   in my teaching career have I met such wonderful students as you .

The possibility of enhancing one’s knowledge is limitless .Graduation小题6:   marks a stage of one’s education .Unceasing asking 小题7: knowledge will unceasingly escalate us to ever higher and higher attainments.

I do believe that your efforts will eventually pay off . I, as well as your other teachers ,am praying that every one of you will be admitted to 小题8:      ideal college.

Love from

Your English teacher

查看答案
单项选择题

CRTSⅠ型轨道板混凝土强度和弹性模量达到设计值的（）%方可施加预应力。

A、75

B、80

C、90

D、100
查看答案