问题
单项选择题 A1型题
属于B细胞的表面标志为（）。
A.CD3
B.CD4
C.CD8
D.CD19
E.CD56
答案
参考答案：D
解析：B细胞表面有CD19、CD20、CD21、CD22和CD29等分化抗原。
搜题请搜索小程序“爱下问搜题”
属于B细胞的表面标志为（）。
A.CD3
B.CD4
C.CD8
D.CD19
E.CD56
参考答案：D
解析：B细胞表面有CD19、CD20、CD21、CD22和CD29等分化抗原。
Earthquakes are common, and thousands of them happen each day. But most are too weak to feel. During a earthquake, there is often a great noise first. Then the earth terribly and many houses down. Railway tracks break and trains go off lines. A great many factories are destroyed. Thousands of deaths are caused, and many more lose homes. Besides the great damage and deaths caused by the earthquake ,other accidents such as fires often . More buildings are destroyed and more deaths caused. It is well-known of the of an earthquake, and for centuries man has been making researches on earthquakes. More than 2,000 years ago, ,a Chinese scientist named Zhang Heng invented a machine which could from which direction the seismic waves（地动波）had come, and this machine is still by scientists today. Now we know much more about earthquakes and they happen, but we still can't tell exactly when and where earthquake will happen, and cannot stop it from happening.
|