车载台无信号显示动车时，视为车列自动溜逸，该装置将施行报警（）秒钟，如不进行解锁将产

男性，72岁，高血压2年，吸烟20年，血压最高185／115mmHg，自行间断服用"罗布麻"片，平时波动在150／100mmHg～170／110mmHg。

该患者降压治疗的目标是（）

A.血压<130／80mmHg

B.血压<140／85mmHg

C.血压<140／90mmHg

D.血压<145／90mmHg

E.血压<150／90mmHg

排气污染物

简述能量的作用。

About fifty years ago, plant physiologists set out to grow roots by themselves in solutions in laboratory flasks. The scientists found that the nutrition of isolated roots was quite simple. They required sugar and the usual minerals and vitamins. However, they did not require organic nitrogen compounds. These roots got along free on mineral inorganic nitrogen. Roots are capable of making their own proteins and other organic compounds. These activities by roots require energy, of course. The process of respiration uses sugar to make the high energy compound ATP, which drives the biochemical reactions. Respiration also requires oxygen. Highly active roots require a good deal of oxygen.
The study of isolated roots has provided an understanding of the relationship between shoots and roots in intact plants. The leaves of the shoots provide the roots with sugar and vitamins, and the roots provide the shoots with water and minerals. In addition, roots can provide the shoots withorganic nitrogen compounds. This comes in handy for the growth of buds in the early spring when leaves are not yet functioning. Once leaves begin photosynthesizing, they produce protein, but only mature leaves can "export" protein to the rest of the plant in the form of amino acids.

It can be inferred from the passage that, in the early spring, the buds of plants ______.

A．"export" protein in the form of amino acids

B．do not require water

C．have begun photosynthesizing

D．obtain organic compounds from the root

求选课在3门以上且各门课程均及格的学生的学号及总成绩，查询结果按总成绩降序排列。请对下列的SELECT-SQL语句填空： SELECT学号，SUM(成绩)AS总成绩FROM选课表； WHERE成绩＞=60 【10】 ORDER BY 【11】 DESC