降低行为发生率的技术不包括（） A.行为契约 B.消退 C.行为代价 D.矫枉过正

人造石的性质特征表现为 （）

A.其结固反应为吸热反应

B.其晶体致密，呈棱柱型

C.其晶体构型为α型

D.其调和速度愈快，结固愈慢

E.其生石膏含量多，结固减慢

稽留高热，四肢温暖，谵妄，白细胞计数增高，血培养阳性是（）

A.革兰阳性细菌败血症

B.革兰阴性细菌败血症

C.菌血症

D.脓血症

E.毒血症

控制概念中最本质的属性就在于必须具有（）。

A.目的

B.手段

C.机制

D.反馈

Recently, I flew to Las Vegas to attend a meeting. As we were about to arrive, the pilot announced with apology that there would be a slight (16) before setting down. High desert winds had (17) the airport to close all but one runway. He said that we would be (18) the city for a few minutes waiting to (19) . We were also told to remain in our seats meanwhile with our seat belts fastened (20) there might be a few bumps(颠簸). Well, that few minutes turned into about four-five minutes, including a ride that would make a roller coaster(过山车) (21) by comparison. The movement was so fierce that several passengers felt (22) and had to use airsickness bags. As you might guess, that’ s not a good thing to have happen in a(n) (23) space because it only (24) to increase the discomfort of the situation.

About twenty minutes into the adventure, the entire airplane became very (25) There was now a sense of anxiety and fear that could be (26) noticed. Every passenger simply held on for dear life …except one. A (27) was having a good time！ With each bump of the (28) , he would let out a giggle (咯咯地笑)of delight. As I observed this, I (29) that he didn’t know he was supposed to be afraid and worried about his (30) . He neither thought about the past nor about the future. Those are what we gown--ups have learned from (31) . He was (32) the ride because he had not yet been taught to fear it. Having understood this, I took a deep breath and (33) back into my seat, pretending I was (34) on a roller coaster. I smiled for the rest of the flight. I even (35) to giggle once or twice, much to the chagrin(随恼) of the man sitting next to me holding the airsickness bag.

22（）

A.watching 

B.visiting 

C.circling 

D.crossing

下图中，遮光角是指（）

A.α角

B.β角

C.两个都是

D.两个都不是