技术水平不变是指生产中所使用的技术没有发生变化。

曲线f（x）=x+lnx在点（1，1）处的切线方程是______．

下列说法正确的是（　　）

A．物质的密度与它的质量成正比，与它的体积成反比

B．对某种物质而言，它的质量和体积成正比

C．某种物质的密度大小，与它的质量和体积有关

D．只要测出物质的密度，就可以确定它是哪种物质

Our little boy came up to his mother in the kitchen one evening while she was fixing supper, and handed her a piece of paper that he had been writing on. After his morn dried her hands on an apron, she read it, and this is what it said:
For cutting the grass $ 5.00
For cleaning up my room this week $ 1.00
For going to the store for you $ 0.50
Baby-sitting my kid brother while you went shopping $ 0.25
Taking out the garbage $ 1.00
For getting a good report card $ 5.00
For cleaning up and raking the yard $ 2.00
Total owed : $ 14.75
Well, I’ll tell you, his mother looked at him standing there expectantly, and boy, could I see the memories flashing through her mind. So she picked up the pen, turned over the paper he’d written on, and this is what she wrote:
For the nine months I carried you while you were growing inside me, no charge.
For all the nights that I’ve sat up with you, doctored and prayed for you, no charge.
For all the trying times, and all the tears that you’ve caused through the years, there’s no charge.
For all the nights that were filled with dread, and for the worries I knew were ahead, no charge.
For the toys, food, clothes, and even wiping your nose, there’s no charge, son.
When you ______, the cost of my love is no charge.
Well, friends, when our son finished reading what his mother had written, there were great big old tears in his eyes, and he looked straight up at his mother and said: "Mom, I sure do love you. "
And then he took the pen and in great big letters he wrote: "PAID IN FULL. "

Please fill in the blank in the passage with proper words or phrases to complete the sentence. (within 5 words)

镗孔的关键技术是解决镗刀的（）和排屑问题。

A、柔性

B、红硬性

C、工艺性

D、刚性

法国资产阶级革命时，外国封建势力的联军陈兵法国边境，革命处于危急之中。在大兵压境的情况下，一位工兵上尉用一个通宵写出了《莱茵河军队战歌》。马赛营志愿军率先唱着这支歌向巴黎挺进，所有这首歌后来被称为《马赛曲》。歌声充满着爱国激情，使人民热血沸腾，很快传遍了全国。法国人民高唱着这支歌奔赴前线。1759年，《马赛曲》被定为法国国歌。 以上材料表明 [ ]

①优秀文化给人以特有的感召力，使人深受震撼 ②优秀文化可成为照亮人们心灵的火炬，引领人们前进的旗帜 ③优秀文化可以培养健全的人格 ④优秀文化是人们文化素养的核心和标志

A、①②

B、②④

C、①③

D、①④