问题 单项选择题 A1/A2型题

牙石的致病原理为()

A.机械刺激牙龈

B.引起口臭

C.附着大量菌斑

D.导致颈部龋

E.引起色素沉积

答案

参考答案:C

单项选择题 A型题
阅读理解

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阅读短文,根据所读内容在文后1-10的空格里填上适当的单词或短语。注意:每空不超过3个单词。

                                              Firecrackers greet return of Chinese astronauts

     China's second manned spacecraft returned on October 17 after orbiting the earth for five days. Astronauts

Fei Junlong, 40, and Nie Haisheng, 41, were flown to Beijing where they were given a hero's welcome after

their Shenzhou VI space capsule touched down in their remote steppes of the northern Chinese region of Inner

Mongolia.

     The two men were in good health after orbiting the earth 76 times covering 3.25 million kilometers. State

media hailed the mission as a technological breakthrough and this proved to the world China's power.

     Soon after the craft landed at 4:33 am (20:33 GMT), barely l km (half a mile) from its target, jubilant

residents in Fei's and Nie's hometowns set off firecrackers and performed traditional dragon and lion dances,

beating gongs and drums.

     "The motherland is so great!" the official Xinhua news agency quoted Fei's father as saying. Fei's mother

wept on learning of his safe return.

     State television gave live broadcast of the astronauts coming out of the spacecraft, unaided, and waving

to the recovery team, cameramen and photographers.

     Tang Xianming, director of the Manned Space Engineering Officer, told a news conference that China

would aim for a spacewalk by 2007 and consider putting a woman in space in the near future.

Firecrackers greet return of 1.____