根据首字母提示完成短文填空。

    Years ago, if a teenager had some problems in his life, he might write them in his diary. Now a teenager w____ the same problems might get on the Internet and write them in his blog. In many ways, a diary and a blog are almost the same. So, what makes a blog d____ from a diary?

    The biggest difference is that a blog is much more public t____ a diary. Usually, a teenager likes hiding his diary book and treats it as one full of s____. Both diaries and blogs tell what happened to the writer that day.

    A blog has both good and bad points (特点). The biggest problem is that anyone can read what you write in your blog. If you are not satisfied with a friend during school and write something bad about him in your diary, he will never know it. H____, if you do this on the Internet, that friend may read your blog and get a____. So we have to be careful of what we write.

    A blog has good points, of course. People choose to write in blogs, they know that their friends will read what they write. If you are f____ sad one day and write in your diary, no one will know about it. If you write the same words in your blog, your friends may quickly w____ back to comfort you or offer you help. Blogs help people stay in close contact and let them know what their friends are doing.

T____ it's a good way to write blogs about everyday life, I still p____ my old diary.

比一比，再组词。

内____　 因____　桌____  差____

肉____　烟____　掉____   看____

演绎式探究

风洞实验室中可以产生方向水平、速度大小可调节的风，用来研究处在流动气体中物体的受力情况．将一个套有木球的细直杆放入风洞实验室，已知球受到的重力为G．球在杆上运动时，球与杆之间的滑动摩擦力跟它们之间的压力成正比，比例系数是k．如图甲所示，将杆沿平行风速的方向固定，调节风速的大小，使球恰能沿杆以速度v匀速运动．再将杆沿竖直方向固定，如图所示，将球从杆的上端由静止释放，保持球下滑过程中所受风力与杆处于水平方向时受到的风力大小相同．（提示：运动物体所具有的动能公式为$\frac{m{v}^2}{2}$，其中m代表物体的质量，v代表物体的运动速度．）则：

注意：信的开头和结尾已给出（不计入词数）。

Dear Wang Lin,

    ……

Yours sincerely,

Li Yue