问题 单项选择题

上下颌骨处于正中关系时,下颌可做开闭运动的最大范围是()

A.15~18mm

B.18~20mm

C.18~25mm

D.25~30mm

E.30~35mm

答案

参考答案:C

解析:正中关系亦称下颌后退位,指下颌不偏左、不偏右,适居正中,髁状突处于关节窝的后位,在适当的垂直距离时,下颌骨对上颌骨的位置关系。它是一个稳定而可重复性的位置,是一个功能性的后退边缘位,如果迫使下颌再向后退,则会由于附着在下颌骨上的肌肉受拉,髁状突后方的软组织受压而感到不适。髁状突在此位置称为正中关系位。下颌依此为轴可作约20mm转动,又称为铰链位。

单项选择题
完形填空

E

71    It might understand more than you think.

A dog named Rico recognizes the names of about 200 objects, say researchers in Germany.   72   Its word-learning skills are as good as those of a parrot or chimpanzee.

In one experiment,the researchers took all 200 items that Rico is supposed to know and divided them into 20 groups of 10 objects.   73   In four tests,Rico got 37 out of 40 commands right.As the dog couldn’t see anyone to get clues,the scientists believe Rico must understand the meanings of certain words.

In another experiment,the scientists took one toy that Rico had never seen before and put it in a room with seven toys whose names the dog already knew.   74    

The correct object was chosen in seven out of 10 tests.suggesting that the dog had worked out the answer by process of removing.A month later,Rico remembered half of the new names,which is even more impressive.

75   Even if they do,they can’t talk back.Still,it wouldn't hurt to sweet-talk your dog

every now and then You might just get a big,wet kiss in return!

A.The owner then told Rico to fetch the object,using a word the dog had never heard before

B.Do dogs more understand us than some friends?

C.It’s hard to know if all dogs understand at least some of the words we say.

D.Be careful what you say around your dog. E.The dog also appears to be able to learn new words

F.Then the owner told the dog to go and fetch one of the items and bring it back.

G.Rico is thought to be smarter than the average dog.