如果氢气球充气时接近饱和状态,升空后不久便会爆裂,主要原因是[ ] A.由于升空

题型:选择题

问题:

如果氢气球充气时接近饱和状态,升空后不久便会爆裂,主要原因是[ ]

A.由于升空后气温降低,气球收缩而破裂

B.由于升空后气温升高,气球膨胀而破裂

C.由于升空后空气密度减小,气压降低,氢气球膨胀而破裂

D.由于升空后空气密度增大,气压升高,氢气球因外界压力太大而破裂

考点:热力环流
题型:选择题

阅读理解。

     Once a group of 17-year-old schoolboys decided to break the world basketball marathon record (马拉

松记录). They wanted to play for ninety hours and that is to add six hours to the record. Each team has

nine players, with five at a time. The boys decided each person would play 21.5 hours and then rest for 2

hours. Then they started at 6 o'clock in the evening.

    The first night was very hard for the players. When it was their turn to rest, they were too excited to fall

asleep at once. After sleeping for a short time, they had to play again. On the second night, they fell asleep

as soon as they stopped. Some of them had trouble with their feet and hands, but the only serious problem

was a psychological (心理上的) one. Each boy was thinking: Why am I doing this? How can I play any longer?

    After the third night, The players knew they could finish the ninety hours. The basketball on the fourth

night was very slow. But in the final hours, the players got better. For the last few minutes, the players looked

as fresh as when they started. How happy everyone was!

1. In the story, there were ______ schoolboys playing basketball marathon.

A. 9

B. 14

C. 17

D. 18

2. Before this basketball marathon, the world record was ______.

A. 84 hours

B. 86 hours

C. 90 hours

D. 96 hours

3. The first night was hard for the players to fall asleep because ______.

A. they were too excited

B. they only slept for a short time

C. no one watched them play

D. it was very long

4. The word "fresh" in the sentence"…the players looked as fresh as when they started" means ______.

A. 新鲜的

B. 兴奋不已的

C. 精神饱满的

D. 伤痕累累的

5. Which of the following sentences is wrong?

A. Some of the boys were hurt when they played.

B. It was hard for the players to fall asleep at night.

C. The boys started playing at 6 o'clock in the evening.

D. In the end, the boys felt happy.

题型:选择题
完形填空。
     Bob and Jane are  1  They live in a small house. The house is   2  a busy street Near their house  3  a
supermarket.   
     There are four people in the family: Bob, Jane, their father and their mother. Their father is a worker.
He   4  a factory not far  5  their house. Their mother is  6  home. She is a housewife (家庭主妇). Bob and
Jane go to school every day. They are  7 . And they go to movies  8 .    
     Bob likes sports. He likes swimming and playing soccer. After school he often plays soccer  9  his
classmates. Jane is a good girl. After school, she often goes home to help her mother  10  the housework.
( )1. A. brothers and sisters
( )2. A. at                 
( )3. A. has                
( )4. A. are working         
( )5. A. in                 
( )6. A. at                 
( )7. A. at the same school  
( )8. A. on weekdays        
( )9. A. and                 
( )10. A. doing             
B. brother and sister
B. in              
B. have            
B. is working       
B. at               
B. in               
B. at the same schools
B. on weekends       
B. with             
B. does              
C. a brother and sister
C. under              
C. is there            
C. works in           
C. for               
C. on                 
C. in the same school 
C. at weekends       
C. but                
C. do                
D. a brother and a sister 
D. on                        
D. there is               
D. works at                  
D. from                  
D. away                      
D. in the same schools      
D. at weekdays             
D. or                       
D. in                    
题型:选择题

汇票中的付款人是否承担必须付款的义务,主要是基于其是否作出()

A、出票

B、背书

C、保证

D、承兑

题型:选择题

简述光肥仪的特点及使用方法。

题型:选择题

车撞伤左腰及腹部,血尿,腹穿有不凝血,B超发现脾破裂、左肾裂伤。治疗应采取

A.经第11肋间探查肾,经腹探查脾

B.经腹探查脾并经腹行肾切除

C.经腹探查肾同时探查脾

D.行腹腔引流并继续输血

E.经腹探查脾。先阻断肾蒂后再探查肾脏

更多题库