视网膜中央动脉阻塞的病因包括以下几项,除了() A.动脉粥样硬化斑下的出血 B.

题型:单项选择题

问题:

视网膜中央动脉阻塞的病因包括以下几项,除了()

A.动脉粥样硬化斑下的出血

B.壁间动脉瘤

C.栓子

D.血栓

E.血管破裂

考点:广东住院医师眼科学眼科学综合练习眼科学综合练习题库
题型:单项选择题

已知线段AB的长为2,P是线段AB的一个黄金分割点,且PA<PB,则PA的长为______.

题型:单项选择题

FITC的最大吸收光谱和最大发射光谱分别为()

A.490~495nm、520~530nm

B.390~395nm、520~530nm

C.590~595nm、520~530nm

D.490~495nm、620~630nm

E.390~395nm、620~630nm

题型:单项选择题

甲、乙两物体从同一地点开始做直线运动,其v-t图象如图所示,下列关于两物体的运动情况,判断正确的选项是(   )

A.在ta时刻两物体速度大小相等,方向相反

B.在ta时刻两物体加速度大小相等,方向相反

C.在ta时刻前,乙物体在甲物体前,并且两物体间的距离越来越小

D.在ta时刻后,甲物体在乙物体前,并且两物体间的距离越来越大

题型:单项选择题

阅读理解。

      Short and shy, Ben Saunders was the last kid in his class picked for any sports team. "Football, tennis

Cricket-anything with a round ball, I was useless, "he says now with a laugh. But back then he was the

object of jokes in school gym classes in England's rural Devonshire. 

     It was a mountain bike he received for his 15th birthday that changed him. At first the teen went biking

alone in a nearby forest. Then he began to cycle along with a runner friend. Gradually, Saunders set his mind

building up his body, increasing his speed, strength and endurance. At age 18, he ran his first marathon.

      The following year, he met John Ridgway, who became famous in the 1960s for rowing an open boat

across the Atlantic Ocean. Saunders was hired as an instructor at Ridgway's school of Adventure in Scotland,

where he learned about the older man's cold-water exploits (成就). Intrigued, Saunders read all he could about

Arctic explorers and North Pole expeditions, then decided that this would be his future.

     Journeys to the Pole aren't the usual holidays for British country boys, and many people dismissed his

dream as fantasy."John Ridgway was one of the few who didn't say, 'You are completely crazy,' Saunders

says.

     In 2001, after becoming a skilled skier, Saunders started his first long-distance expedition toward the North

Pole. He suffered frostbite, had a closer encounter (遭遇) with a polar bear and pushed his body to the limit.

     Saunders has since become the youngest person to ski alone to the North Pole, and he's skied more of the

Arctic by himself than any other Briton. His old playmates would not believe the transformation.

      This October, Saunders, 27, heads south to explore from the coast of Antarctica to the South Pole and back, an 1800-mile journey that has never been completed on skis.

1. The turning point in Saunders' life came when  _____.

A. he started to play ball games

B. he got a mountain bike at age 15

C. he ran his first marathon at age 18

D. he started to receive Ridgway's training

2. We can learn from the text that Ridgway _______.

A. dismissed Saunders' dream as fantasy

B. built up his body together with Saunders

C. hired Saunders for his cold-water experience

D. won his fame for his voyage across the Atlantic

3. What do we know about Saunders?

A. He once worked at a school in Scotland.

B. He followed Ridgway to explore the North Pole.

C. He was chosen for the school sports team as a kid.

D. He was the first Briton to ski alone to the North Pole.

4. The underlined word "Intrigued" in the third paragraph probably means _____.

A. Excited  

B. Convinced

C. Delighted

D. Fascinated

5. It can be inferred tat Saunders' journey to the North Pole ______.

A. was accompanied by his old playmates

B. set a record in the North Pole expedition

C. was supported by other Arctic explorers

D. made him well-known in the 1960s

题型:单项选择题

25G型客车应急电源容量为()。

更多题库