Why does the author say that even gold and silver were inconvenient if you had to buy something expensive?
Why does the author say that even gold and silver were inconvenient if you had to buy something expensive?
可知
两个物体在光滑水平面上相向运动，在正碰以后都停下来，那么这两个物体在碰撞以前（ ）．
两个物体在光滑水平面上相向运动，在正碰以后都停下来，那么这两个物体在碰撞以前（ ）．
关于匀减速直线运动中随着时间的增加，位移和速度大小的说法正确的是（ ）．
关于匀减速直线运动中随着时间的增加，位移和速度大小的说法正确的是（ ）．
The word “obsessed” in Paragraph 2 probably means _____.
The word “obsessed” in Paragraph 2 probably means \_\_\_\__.
形寒肢冷，脘腹冷痛，纳呆呕恶，大便稀溏，肢体浮肿，腰膝酸软，舌淡苔白滑，此证属于（ ）。
形寒肢冷，脘腹冷痛，纳呆呕恶，大便稀溏，肢体浮肿，腰膝酸软，舌淡苔白滑，此证属于（ ）。
0.1摩尔某种烷烃完全燃烧时生成0.5摩尔CO2，则该烃的结构简式是____，这种烃跟氯气发生取代反应，生成的一氯代烃只有一种，该烷烃的结构简式是____，名称是____．
0.1摩尔某种烷烃完全燃烧时生成0.5摩尔CO2，则该烃的结构简式是\_\_\_\_，这种烃跟氯气发生取代反应，生成的一氯代烃只有一种，该烷烃的结构简式是\_\_\_\_，名称是\_\_\_\_．
简谐波某时刻的波形如下图所示，A点在此时刻是向下运动的，则（ ）．
简谐波某时刻的波形如下图所示，A点在此时刻是向下运动的，则（ ）．
According to Ban the Bottle, drinking bottled water costs _____ dollars per year.
According to Ban the Bottle, drinking bottled water costs \_\_\_\__ dollars per year.