关于PCA技术参数，叙述正确的有（）

A.负荷量是最大的有效镇痛浓度

B.单次给药剂量是每次按压PCA键所给的镇痛药剂量

C.锁定时间是2次PCA按键给药之间的时间间隔

D.单位时间最大剂量指最大单位时间内的使用量

E.背景剂量可以减轻患者的操作负担，改善镇痛效果

A narrowing of your work interests is implied in almost any transition from a study environment to managerial or professional work. In the humanities and social sciences you will at best reuse only a fraction of the material (1) in three or four years’ study. In most career paths academic knowledge only (2) a background to much more applied decision-making. Even with a " training " form of degree, (3) a few of the procedures or methods (4) in your studies are likely to be continuously relevant in your work. Partly this (5) the greater specialization of most work tasks compared (6) studying. Many graduates are not (7) with the variety involved in (8) from degree study in at least four or five subjects a year to very standardized job (9) . Academic work values (10) inventiveness, originality, and the cultivation of self-realization and self-development. Emphasis is placed (11) generating new ideas and knowledge, assembling (12) information to make a " rational " decision, appreciating basic (13) and theories, and getting involved in fundamental controversies and debates. The humanistic values of higher (14) encourages the feeling of being (15) in a process with a self-developmental rhythm. (16) , even if your employers pursue enlightened personnel development (17) and invest heavily in " human capital " —for example, by rotating graduate trainees to (18) their work experiences—you are still likely to notice and feel (19) about some major restrictions of your (20) and activities compared with a study environment.

19（）

A.strange

B.ashamed

C.funny

D.sorry