液体在直径相同的直管中流动时的压力损失称为（）
A、传动损失
B、能耗损失
C、流动损失
D、沿程损失
参考答案：D
Great changes have taken place in that college. It’s no longer _____ it was 20 years
ago, _____ it was so poorly equipped.
A．what; when
B．that; which
C．what; which
D．when; that
一国一定时期内某商品的进口量小于出口量称为（）
A、净进口
B、净出口
C、贸易顺差
D、贸易逆差
