同一种属所有正常个体18分子所共同具有的抗原特异性标志
A．Ig同种型B．Ig同种异型C．Ig独特型D．lg的CDR区E．Ig的恒定区
参考答案：A
小题1: After about three （星期）holiday, we came back to school.
小题2:My mother has so many (家务)to do every day.
小题3:She is looking forward to (收到) letters from her friends.
小题4:You should do your homework more_______(仔细地).
小题5:It makes me feel (自豪的) when I see the national flag of China.
小题6:Computer is one of the greatest (发明) . I can’t imagine life without it.
急性化脓性中耳炎最常见的感染途径（）
A.血行感染
B.淋巴道感染
C.外耳道鼓膜途径
D.咽鼓管途径
E.颅骨途径
