有某温度时某物质的饱和溶液,在温度不变的条件下蒸发一部分溶剂后,有晶体析出,则该溶液[ ]
A、仍为饱和溶液
B、溶液中溶质的质量分数变小
C、溶解度变小
D、变成不饱和溶液
答案:A
Mike's brother often _____ the number 2 bus _____ school. [ ]
A. brings; to
B. takes; to
C. by; to
D. catch; to
请解释需求量变动和需求变动之间的区别?