除去亲脂性色素用( )法 A．酸减法 B．水醇法 C．醇醚法 D．活性炭 E．盐析

视网膜母细胞瘤具有下列临床特征（）

A.患者多为婴幼儿，就诊时多有在瞳孔区内发现黄或白色反射史

B.扩瞳检查可在眼底上见到很特殊的黄或白色隆起肿块

C.眼眶X线显示细碎钙质阴影

D.超声波检查探测无实质性肿块回波

E.常为单眼，单灶发病

临床上神经系统定性诊断主要根据

A．起病形式、症状的发生顺序、疾病的演变过程及必要的特殊检查
B．神经系统的体征
C．患者的家族史及必要的特殊检查
D．特殊检查
E．以上均不是

Without proper lessons, you could ______ a lot of bad habits when playing the piano.

A．keep up

B．pick up

C．draw up

D．catch up

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 fine 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 with organic 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.

Where is this passage likely to be found

A．A newsletter.

B．A magazine.

C．A storybook.

D．A novel.

主动脉瓣关闭不全（）

A.舒张期隆隆样杂音

B.舒张期叹气样杂音

C.连续性机器样杂音

D.乐鸣音杂音

E.收缩期菱形杂音