二手船价格主要按船龄或按每载重吨单价指标估算，后者每载重吨单价会随着船舶吨位的增大而增大。
参考答案：错
频谱多普勒在零位基线向上的血流频谱，表明血流是（）
A.反向的层流血流
B.反向的湍流血流
C.朝向探头的血流
D.背离探头的动脉血流
E.背离探头的静脉血流
Miss Chen was not pleased. I made _______ in my English test. [ ]
A. a few mistakes
B. few mistakes
C. a little mistakes
D. little mistakes
