“六学二馆”是( )中央官学体系的简称
A．隋朝
B．宋朝
C．唐朝
D．西汉
参考答案：C
解析： “六学二馆”是唐朝中央官学的简称，应记住。
____ succeed in doing anything .
A．Only by working hard we can
B．By only working hard we can
C．Only we can by working hard
D．Only by working hard can we
压缩机串联工作可增大气流的排出压力，压缩机并联工作可增大气流的输送流量。（）
