咬合力与牙周支持力不协调时可造成牙齿支持组织的病理损害，将此称为（）。 A.边缘性龈

已知曲线C上的动点P到点（1，0）的距离与到定直线L：x=-1的距离相等，

（1）求曲线C的方程；

（2）直线m过（-2，1），斜率为k，k为何值时，直线m与曲线C只有一个公共点，有两个公共点；没有公共点？

患者男，66岁，左上87654右上567缺失，拟行可摘局部义齿修复，但患者对塑料严重过敏，余牙及缺牙间隙正常 。

若对该患者基牙右上8设计正型卡环，其固位力多少为宜 （）

A.200～300g

B.300～400g

C.400～500g

D.500～600g

E.600～700g

Somali pirates(海盗) robbed three Thai fishing ships with 77 sailors on board nearly l，200 Miles off the Somali coast，the farthest-off-shore attack to date，an officer said Tuesday.

Pirates have gone farther south and east in answer to increased patrols(巡逻)by warships off the Somali shore. The robbing of the three ships Sunday was about 600 miles outside the normal operation area for the international force，said a spokesman．

The spokesman said the attack so far out at sea was a clear sign that the international patrols against pirates were having a “marked effect on pirate activity in the area”．

“Once they start attacking that far out，you’re not even really talking about the Somali basin or areas of water that have any connection with Somalia,” said an officer，Roger Middleton．“Once you’re that far out，it's just the Indian Ocean，and it means you’re looking at trade going from the Gulf to Asia，from Asia to South Africa.”

"This is the farthest robbing to date．They are now operating near the Maldives and India,”said another officer．

The three ships--the MV Prantalay l l，12，and l 4—had 77 members on board in total．All of them are Thai, the spokesman said．Before the Sunday robbing，pirates held l l ships and 228 sailors．

Pirates have increased attacks over the past year in hopes。f catching more dollar payments. Because of increased patrols and defenses on board ships，the success rate(率)has gone down，though the number of successful attacks has stayed the same year over year.

1.The pirate attack reported in the text happened____________．

A．far out in the Indian Ocean

B．in the normal patrol area

C．near the Somali, coast

D．in the south of Africa

2．According to the text, which can best describe the situation of the pirate problems?

A．More goods on board are lost.

B．Pirate attacks happen in a larger area now.

C．The number of attacks has stayed the same these years.

D．Pirate attacks are as serious as before along the Somali coast.

3．Which is true about the warship patrols according to the text?

A．The patrols are of little effect.

B．The patrols are more difficult.

C．More patrols are quite necessary even in Asia.

D．The patrols only drive the pirates to other areas.

4．How many sailors were held by the pirates up to the time of the report?

A．228.             B．77.              C．383.             D．305.

什么是后期A和后期B？在这两个时期，染色体分离的机理有何不同？

买卖有价格涨跌幅限制的证券，在价格涨跌幅限制内的申报为有效申报，超过涨跌幅限制的申报为无效申报。( )