锰中毒作用主要表现为（）
A.消化系症状
B.呼吸系症状
C.泌尿系症状
D.贫血
E.神经系统的锥体外系损害症状
参考答案：E
肺放线菌病的特点包括（）
A.可穿透胸壁形成窦道
B.胸腔积液
C.心包积液
D.沿肋骨处有骨膜增生或骨质缺损
E.肺门淋巴结钙化
It was only after World War II had drawn to a close ______ in the United States.
A．did the baby boom begin
B．that the baby boom began
C．when the baby boom began
D．then the baby boom began
