胸骨左缘第3、4肋间隙
A.三尖瓣区B.肺动脉瓣区C.二尖瓣区D.主动脉瓣第二听诊区E.主动脉瓣区
参考答案:D
The situation requires that the manager _____ there immediately. [ ]
A. go
B. goes
C. has gone
D. had gone
焦油加工的主要任务是获得酚、萘、蒽等纯产品和()等粗产品。