问题 单项选择题

以下符合短暂性脑缺血发作影像学改变的是()。

A.CT低密度灶

B.CT高密度灶

C.MRITI低信号

D.MRIT2高信号

E.MRI弥散加权成像高信号

答案

参考答案:E

解析:CT低信号及MRIT1低信号、T2高信号都是脑梗死的影像学表现,它的出现代表了组织细胞的不可逆损伤。CT高信号是脑出血的影像学改变。.MRI弥散加权成像反映了水分子的运动,并不代表组织的不可逆损害。局限性水肿在弥散成像上也表现为高信号灶,随着水肿的消退,弥散成像可完全恢复正常。

阅读理解

Charlie studied Chemistry in a famous college for four years. He studied hard and did well in all his subjects. He hoped to become a good teacher. This year he left the college and began to work in a middle school. He likes his students and wants them to get good marks so he does his best to make his classes lively and interesting.

One day he carefully explained a chemical reaction(反应)to the students of Grade 2 in the chemistry lab.

“Be careful. Everyone,” he said loudly. “Before I make the experiment, there’re twenty five atoms of carbon(碳原子), but after I finish it, there’re twenty four atoms of carbon left!”

He stopped to watch the classroom and hoped his students would go on explaining it. But the young men looked at each other and nobody answered him. He had to ask, “What happens? What makes the atom disappear? ”

The classroom was very quiet and none of the students looked at their teacher.

“Who can tell us where it has gone?”

Suddenly a soft voice came from the back row, “We did not see anybody leave the lab!”

60.Charlie began to work in the middle school because _______.

A. he had been in the school for four years 

B. he couldn’t do anything except teaching

C. he hoped to become a good teacher        

D. he did well in all his subject

61. Charlie hoped ____,so he does his best to make his classes lively and interesting.

A .all his students could understand him                    

B .his students wouldn’t be afraid of him

C. his students carefully watched him doing the experiment

D. his students would do well in chemistry.

62. That day Charlie wished ____.

A. his students could learn the chemical reaction

B. his students should find the atom of carbon

C. his students could count(数) the atoms of carbon

D. his students could make the experiment

63. The students couldn’t answer Charlie’s questions because ____.

A. none of them had seen the atoms                         

B. they were afraid of the teacher

C. the chemical reaction was too complicated            

D. they all wanted to drop the subject

多项选择题