问题 选择题

用显微镜观察小鱼尾鳍内血液流动时,辨别毛细血管的方法是( )

A.管腔较细

B.管腔较粗

C.红细胞成单行通过

D.血液流向心脏

答案

答案:C

题目分析:用显微镜观察小鱼尾鳍时,判断动脉、静脉和毛细血管的依据是:从主干流向分支的血管是动脉,由分支汇集而成的血管是静脉,红细胞单行通过的是毛细血管.其中毛细血管的特点是:管腔最细,只允许红细胞单行通过;管壁最薄,只有一层上皮细胞构成;血流速度最慢;这些特点都有利于血液与组织细胞间进行物质交换.故选:C

阅读理解

.

第三部分:阅读理解(共20小题,每小题2分;共40分)

阅读下面短文,掌握其大意,然后从各题的A、B、C、D四个选项中,选出最佳选项,并在答题卡上将该项涂黑。

Several interesting American museums tell about health subjects. One is the Doctor Samuel D. Harris National Museum of Dentistry. It is at the University of Maryland in Baltimore. That is where the first college in the world to train dentists began. The museum tells about the history of the medical treatment of teeth. Visitors can see some frightening devices that once were used to remove infected teeth. They also can see sets of teeth made of animal bone. They were made for a famous American —— the first President, George Washington.

Most people do not consider a visit to the dentist their idea of a good time. However, the director of the museum says he wants to make the museum a funny place to visit. He says he also wants to teach visitors about the importance of taking care of their teeth.

Another museum collects devices that help people hear. The Kenneth W. Berger Hearing Aid Museum is at Kent State University in Kent, Ohio. The museum has more than three-thousand hearing aids from around the world. They include old and strange devices. Some hearing aids were made to look like other objects. That is because in the past many people did not want anyone to know they were wearing a hearing aid.

56. It is common for people to think it uneasy to pay a visit to ____.

A. the University of Maryland            B. the Museum of Dentistry

C. the Hearing Aid Museum              D. the dentist

57. The text mainly tells about _____.

A. museums in the US               B. interesting American museums

C. American museums with health subjects

D. the history of the medical treatment of teeth

58. What do we learn about George Washington from the text?

A. He once visited the National Museum of Dentistry.

B. He considered the Museum of Dentistry a fun place to visit

C. His artificial (人造的) teeth were collected in the National Museum of Dentistry.

D. His teeth seemed to be made of animal bone.

59. The underlined word “devices” in the first and last paragraph probably means _____.

A. ways        B. strategies        C. tools          D. desires

问答题