X线照片产生灰雾的原因，主要有A．胶片本底灰雾 B．焦点外X线 C．显影处理 D．被

（B）

Mr. and Mrs. Smith always spent their summer holidays in New Jersey in the past , staying in a small inn at the foot of a hill . One year , however Mr. Smith made a lot of money in his business , so they decided to go to London and stay at a really good hotel while they went touring around the famous city .

They flew to London and arrived at their hotel late one evening . They expected that they would have to go to bed hungry , because in that small inn in New Jersey , no meals were served after seven . They were therefore surprised when the man who received them in the hall asked whether they would take dinner there that night .

“ Are you still serving dinner ? ” asked Mr. Smith .“ Yes , certainly , sir , ” answered the man . “ We serve it until half past nine . ”“ What are the times of meals then ? ” asked Mr. Smith .“ Well , sir ” answered the man , “ we serve breakfast from seven to half past eleven in the morning , lunch from twelve to three in the afternoon , tea from four to five , and dinner from six to half past nine . ”“ But that hardly leaves any time for us to see the sights of London , ” said Mrs. Smith .

26. Mr. and Mrs. Smith in the past______________ .

A. has often stayed in a big hotel in New Jersey

B. had travelled to many places

C. often stayed in a small inn

D. had made a lot of money

27. They decided to go to a really good hotel because____________ .

A. it was famous

B. it was difficult to find a cheap hotel

C. it was near many interesting places

D. they now had enough money

28. When they arrived at the hotel , they found___________ .

A. no meals were served after seven

B. dinner was still being served

C. their plane had arrived too late

D. they had to go to bed hungry

29. When the man told them the times of meals at the hotel , Mrs. Smith felt_______ .

A. disappointed   B. excited   C. delighted   D. satisfied

30. Mrs. Smith_____________ .

A. thought she would have plenty of time to see the sights

B. was afraid they would have no time to tour around London

C. thought the hotel was not as good as the small inn

D. thought the hotel was much better than the small inn for its good meals

患者男，34岁，车祸伤致右大腿肿胀、疼痛、畸形，伴活动受限1天。查体：右大腿肿胀，中部可见明显成角畸形，骨擦感，足背动脉可扪及，踝关节活动正常。

应首先做的辅助检查是（）.

A.X线

B.MRI

C.B超

D.CT

E.ECT

F.心电图

如图，一固定斜面上两个质量相同的小滑块A和B紧挨着匀速下滑，A与B的接触面光滑．已知A与斜面间的动摩擦因数是B与斜面间的动摩擦因数的2倍，斜面倾角为α，B与斜面间的动摩擦因数是（　　）

A．

2

3

tanα

B．

1

2

tanα

C．

1

3

tanα

D．tanα

2013年11月，一位清华的博士生放弃留校做科研的机会，与北京一所重点中学签约做数学老师。他的导师在博客上写下了“大材小用”、“太过现实的社会环境让人才流失”的惋惜与困惑。也有网友说“少了一个搞科研的，科研界不会伤‘元气’；多了一个搞教学的，也许教育界可能升起一颗‘明日之星’。”对导师和网友的言论，正确的看法的是（）

A.导师是错误的，培养人才的社会科学比自然科学更重要

B.网友是错误的，必须充分认识科学技术是第一生产力

C.都有合理性，我们既要坚持核心价值，又要尊重差异，包容多样

D.都是错误的，是非善恶不能混淆，反对和倡导什么，必须旗帜鲜明

患者男性，67岁，因先兆晕厥行颈动脉窦按摩检查。

颈动脉窦按摩的原理是（）

A.提高迷走神经张力，减慢窦房冲动发放频率

B.提高迷走神经张力，缩短房室结传导时间

C.提高迷走神经张力，缩短房室结不应期

D.提高交感神经张力，缩短房室结传导时间

E.提高交感神经张力，减慢窦房冲动发放频率