搜题请搜索小程序“爱下问搜题”
问题 单项选择题

男性，邱岁，查体心底部有舒张期哈气样杂音，以胸骨右缘第2肋间最响，第二心音亢进，血压170/90mmHg，胸片提示主动脉增宽扭曲，心影靴形，最可能的诊断是

A．风湿性主动脉瓣关闭不全
B．先天性心脏病，二叶式主动脉瓣
C．主动脉粥样硬化，主动脉瓣关闭不全
D．肺动脉高压，相对肺动脉瓣关闭不全
E．高血压性心脏病

答案

参考答案：C

单项选择题

仅由台湾籍的爱国民主人士组成的民主党派是（）。

A、中华职业教育社

B、第三党

C、“台盟”

D、九三学社
查看答案
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.

The word "barren" underlined in Paragraph 1 most probably means _______ .

A．lifeless

B．frigid

C．hard

D．uncovered
查看答案