关于脊髓内部结构的描述下列哪项是错误的（）
A.灰质呈蝶形，贯穿脊髓全长
B.灰质位于脊髓中央，白质位于灰质周围
C.脊髓是中枢神经系统的低级中枢
D.各段灰质均有前角、侧角和后角
E.中央管向上通第四脑室
参考答案：D
解析：脊髓横断面上，中央为神经细胞核团组成的灰质，呈蝶形。中心有中央管，外面是上、下传导束组成的白质。中央管前、后连合部分的灰质称为前、后连合，其他部分分为前、后角。颈8到腰2节段灰质有侧角，内主要是交感神经细胞。
| 阅读理解。 |
| Can a star basketball player also be a star hip-hop singer? If you ask Shaquille O'Neal and some of his NBA fellows, they'll say "Sure". In the NBA, hip-hop music is as common as the jump shot. Hip-hop is similar (相似的) to rap (说唱) music and is especially popular with young African Americans. This music is played before basketball games or during halftime. Many of the players, like Shaquille O'Neal of the Los Angeles Lakers, write rap rhymes when they travel on airplanes from one city to another. The NBA has a closer connection to hip-hop than any other sports league. This is partly because of the large number of African-American players, but also because the basketball league just loves hip-hop. Every February, the NBA invites popular rap singers to perform (表演) at its All-Star weekend. When they play basketball, some of the younger stars even try to look like hip-hop singers. Like rap stars, they don't smile in photographs and videos. They try to trouble the players on the other team by looking tough(凶). "Hip-hop is just part of many players'culture (文化) ," says Kerry Kittles, a player on the New Jersey Neis team. "All of us grew up listening to rap and playing basketball, and the rappers grew up doing the same thing. A lot of players want to be rappers, and a lot of rappers would like to be players." Master P. is a famous rap star who wants to be a basketball player. The Charlotte Homets and the Toronto Raptors have invited him to their training camps. They enjoy listening to his music, but many people think that he is not good enough at basketball to be on an NBA team. Shaquille O'Neal, whose nickname is Shaq, is the greatest example of an NBA player who became a rapper. He has made four successful rap albums. One of his rap songs, "It Was All a Dream," tells how he felt when he became successful. |
| 1. Why don't some younger players try to smile or look friendly in photos? |
[ ] |
| A. They try to trouble the players on the other team. B. They try to look like hip-hop singers. C. They try to be successful in their playing. D. They try to pretend (假装) to be famous. |
| 2. The song "It Was All a Dream" expresses ___________. |
[ ] |
| A. O'Neal's feelings when he became a success B. a player's interest in rap music C. people's wish to become a player D. people's dream to be a rapper |
| 3. The best title of the text is "___________". |
[ ] |
| A. The NBA All-Star Weekend in America B. A Successful Player ——O'Neal C. Basketball Stars Become Hip-Hop Singers D. Popular Music and Sports in U. S |
| 4. What do you know about the Charlotte Hornets and the Toronto Raptors? |
[ ] |
| A. They are famous basketball players. B. They are famous basketball teams. C. They are well-known hip-hop singers. D. They are two training places |