猩红热的病原体为革兰染色阴性的A组β型溶血性链球菌。
参考答案：错
—When did the famous writer die?
—In 1988. He ______ for twenty years. [ ]
A. has died
B. has been dead
C. died
D. is dead
隧道内增设密井暗管施工，施工期间速度不超过（）。
A.5km/h
B.15km/h
C.25km/h
D.45km/h
