木枕地段捣固时，应在钢轨两侧（）范围内捣实道床，轨下部分加强捣固。 A.380mm

An artist went to a beautiful part of the country for a holiday, and stayed with a farmer. Every day he went out with his paints and brushes and painted from morning to evening, and then when it got dark, he went back to the farm and had a good dinner before he went to bed.

At the end of his holiday he wanted to pay the farmer, but the farmer said, “No, I don’t want money… but give me one of your pictures. What is money? In a week it will all be finished, but your painting will still be here.”

The artist was very pleased and thanked the farmer for saying such kind things about his pictures. The farmer smiled and answered, “It’s not that. I have a son in London. He wants to become an artist. When he comes home next month, I’ll show him your picture, and he will not want to be an artist any more, I think. ”

小题1:__________ people are mentioned (提到) in the article.

A．Two

B．Three

C．One

D．Many小题2:The artist lived with the farmer __________.

A．for about a month

B．for a year

C．for a holiday

D．for the farmer’s son小题3:The farmer asked the artist to give him a picture because __________.

A．he liked his picture

B．he didn’t want his money

C．he wanted to sell his pictures for some money

D．he wanted to show it to his son小题4:The artist was very pleased and thanked the farmer because __________.

A．the farmer didn’t want him to pay him

B．the farmer decided to let his son learn from him

C．the farmer’s son would be an artist like him

D．he thought the farmer praised (表扬) him for his pictures

患者男，55岁，双下肢无力、行走不稳2年，加重伴排粪无力3个月。查体：脐以下皮肤针刺觉减退，双下肢肌张力略高，双膝腱反射活跃，双侧Babinski征阳性。MRI示T₃～T₄OLF，压迫硬膜囊；T₅～T₆OPLL，压迫硬膜囊；T₁₀～L₁OLF，压迫硬膜囊及脊髓。

术后第3天引流量为150ml，颜色清亮，下列说法不正确的是（）

A.应立即拔出引流管

B.可适当延长引流管留置时间

C.可诊断为脑脊液漏

D.拔出引流管后，嘱患者保持俯卧位5～7d

E.引流管留置时间不宜过长，以免发生感染

由于反映活动的形式不同，知识可以分为陈述性知识与( )

A．程序性知识
B．实用的知识
C．直观的知识
D．可应用的知识

源皮距的描述正确的是（）

A.放射源中心到达体表皮肤照射中心的距离

B.放射源中心到达体内肿瘤所参考点的距离

C.放射源到机架旋转中心的距离

D.放射源到限光筒准直器底面的距离

E.体表照射中心到体内肿瘤所参考点的距离

数字基带信号有哪些常用的形式？它们各有什么优点？它们的时域表达式如何？