石墨炉原子吸收分光光度法测定污染源烟道气中镉的特征谱线为228.8nm。

元宵节石家庄的昼夜长短情况及其变化趋势是

A．昼长夜短，白昼在变长

B．昼长夜短，白昼在变短

C．昼短夜长，白昼在变短

D．昼短夜长，白昼在变长

根据对话内容，从方框内的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

A：Hello, uncle Wang!

B：Hello, Bob!   小题1:  You look worried and upset.

A： 小题2:  I really need your help.

B：What do you mean?

A： 小题3:  But now it becomes more and more difficult since I am in Grade Three. My parents don’t

allow me to play basketball.

B：Maybe your parents are right.  小题4:  

A：I see. I do well in my lesssons and I think I should be allowed to do the things that I am interested in.

B：OK.   小题5: 

A：Thank you uncle Wang. It’s very kind of you.

Work must come first.

I’ll talk with your parents about the problem.

My parents like me to play baksetball.

What’s wrong with you?

The problem is that I love basketball.

I have a problem.

You can ask your parents to buy you a ticket.

忏宿冤凤姐托村妪 释旧憾情婢感痴郎

一般填缝料应（）更换一次

请解释产品整体概念的含义是什么？