某轮船顺流航行3小时，逆流航行5小时，已知轮船的静水速度为a千米/小时，水流速度为b千米/小时，轮船共航行了（ ）千米．
（8a﹣2b）
列宁认为达尔文“第一次把生物放在完全科学的基础之上”，其“完全科学”是指 [ ]
A．符合宗教教义
B．用实验方法进行研究
C．创立生物进化理论
D．将生物进化理论应用于社会研究
Speaker. A: I'm not ever going to that shop near school. They overcharge me every time. Speaker B:______
A．How much do they overcharge you every time
B．You must be mistaken. They provide good service.
C．Me neither. I stopped going there a long time ago.
D．That shop is the closest one to our school.
