上颌窦炎()乳突炎()A.眼眶上缘压痛 B.鼻根部与眼内眦部压痛 C.乳突部压痛 D

卡环臂进入倒凹一般为

A．0.5～0.75mm
B．0.25～0.5mm
C．1～1.5mm
D．2mm
E．0.5mm

我会仿写。

例：有花有草

有____有____　　有____有____

I have a habit of taking a coffee, which makes me feel _____when I have to stay up late. [      ]

A. adequate          

B. adequate

C. sensitive

D. energetic

It is impossible not to make a mistake at some points in your life. We may as well accept that something will go wrong and we will be to blame. It is therefore sensible to work out some strategies for apologizing, and the best way to apologize is by letter. This way you can take care over every work you write— which you can’t do if you say sorry to someone in person.

We all say or do something that we wish we hadn’t said or done. You may say something that accidentally hurts someone, or you may provide a service which doesn’t come up to the standards that a client or customer expected.

You may feel that it was a genuine mistake which couldn’t be avoided. Rather than dwell on the mistake, you should quickly try to remedy（修补）the problem. An effective letter of apology is an important part of that process.

For the contents of the letter, just remember TABS—Timing, Action, Brevity, Sincerity.

The timing of a letter of apology is essential—it must be sent as soon as possible. Any delay in our sending the letter will only compound the problem. In this case “Better late than never” is not the best motto! The longer you wait before you wait before writing a letter of apology, the more it will seem that you have been coerced（被迫）into writing it.

Although it is important to recognize what has gone before, it is also essential to detail the action you plan to take to rectify whatever it was you did wrong. Research has shown that some indication that you have thought about what future action you plan to take is always well received.

A letter of apology should be brief and the word “sorry” should appear no more than twice. Indicate that you are aware using it a second time—“once again, I am so sorry for…” or “as I said earlier, I am really sorry about…”. Finally, the tone of the letter has to be sincere. In fact, the combination of all the above factors will help in this respect.

And don’t think that letters are out of date in the email—oriented 21st century. An apology email can be worse than no apology at all!

小题1:What kind of advice does the text suggest about apologizing?

A．It’s a good idea to write a letter of apology as soon as something has gone wrong.

B．It’s a good idea to send several emails to apologize.

C．Write a long letter apologizing several times to make your point.

D．Wait to see how they react to your letter before planning to do anything.小题2:What kind of things do you NOT apologize for?

A．A service that is not as good as it should be.

B．Genuine mistakes.

C．Car accidents.

D．Causing offence or hurt.小题3:The underlined expression “Rather than dwell on the mistake” in the third paragraph means you _____.

A．should not waste time worrying about what happened.

B．should consider the problem

C．should forget about what happened.

D．should analyse who was at fault.小题4:How can timing compound problems?

A．If you write immediately, they will be suspicious.

B．If you leave it for a few days, they will know it is your idea to write.

C．Waiting for a few days before you write will show your sincerity.

D．Waiting too long will make it worse because they won’t believe you mean it.

如图甲所示，弯曲部分AB和CD是两个半径相等的圆弧，中间的BC段是竖直的薄壁细圆管(细圆管内径略大于小球的直径)，分别与上下圆弧轨道相切连接，BC段的长度L可作伸缩调节。下圆弧轨道与地面相切，其中D、A分别是上下圆弧轨道的最高点和最低点，整个轨道固定在竖直平面内。一小球多次以某一速度从A点水平进入轨道而从D点水平飞出。今在A、D两点各放一个压力传感器，测试小球对轨道A、D两点的压力，计算出压力差ΔF。改变BC的长度L，重复上述实验，最后绘得的ΔF－L图象如图乙所示。(不计一切摩擦阻力，g取10 m/s²)

(1)某一次调节后，D点的离地高度为0.8 m，小球从D点飞出，落地点与D点的水平距离为2.4 m，求小球经过D点时的速度大小；

(2)求小球的质量和弯曲圆弧轨道的半径。