属于北朝的科学家有
①贾思勰②祖冲之③郦道元④张衡[ ]
A．①②
B．③④
C．①③
D．②④
答案：C
As a conductor, Leonard Bernstein is famous for his intensely vigorous and exuberant style.
A．extreme
B．enthusiastic
C．prosperous
D．nervous
渣中的P2O5对钢包炉衬侵蚀的影响最大。
