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问题 单项选择题

患者男性，25岁，右大腿根部刀伤，出现疼痛，肿胀，活动受限。局部血管超声检查显示股动脉、股静脉之间见一无回声管道，其近端动、静脉管径明显增宽，管道处可见从动脉流向静脉的五彩镶嵌血流，静脉内出现动脉化血流频谱，为高速低阻型，其超声诊断最可能为（）。

A.股动脉血栓

B.股静脉血栓

C.股动静脉瘘

D.股静脉瓣功能不全

E.假性动脉瘤

答案

参考答案：C

解析：由题干我们知道该患者右大腿根部刀伤后，超声检查显示股动脉、股静脉之间见一无回声管道，该处可见从动脉流向静脉的五彩镶嵌血流，说明动脉、静脉之间有一瘘口，应为股动静脉瘘。

单项选择题

西餐宴会服务员的平均工作量是每人负责（）客人的服务。

A、3

B、4

C、5

D、6
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单项选择题

Lichens may grow on the bark of a tree in a steaming tropical rain forest, on the bricks of big city buildings, on rocks in hot springs, on wind-swept mountaintops, and in the driest desserts. In the arctic, they provide the principal food for caribou, and they are one of the few plants that grow in Antarctica. They are pioneers, appearing in barren rocky areas and starting the formation of soil in which mosses, then ferns, and then other plants can take root.
Lichens are a partnership of two plants — fungi and algae. The lichen body is made up of a network of fungal strands. In the upper layers of these grow groups of algae. The two organisms live together to the benefit of both, a relationship known as symbiosis. The fungi provide support, absorb water, and shelter the tender algae from direct sunlight. The algae carry on photosynthesis and provide the fungi with food. The algae can live independently and are recognizable as a species that grows alone. The fungi, on the other hand, cannot live apart from their partners. They can be placed in known classes of fungi but are unlike any species that lives independently.
So definite are the form, color, and characteristics of these double organisms that for hundreds of years, they were classified as one. More than 15,000 "species" were named. If these organisms are classified as separate species, it is difficult to fit them into the existing system of classification. But if they are classified separately, these species of fungi seem rather strange. Lichens are a splendid example of the difficulties faced by taxonomists in classifying species.

Lichens may NOT grow ______ .

A．in the tropical woods

B．on the ceilings of city buildings
C．on rocks in hot springs

D．in dry desserts
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