Although bike-sharing has some problems such as disorderly parking, it remains popular in Shenzhen.
A:is never
B:is still
C:isn't always
人体胚胎发育时所需要的营养物质主要来源于母体.(判断对错)
黄铜矿经初步处理后,所得溶液甲中的溶质为Fe2(SO4)3、CuSO4及H2SO4,利用如图实验可制取补血剂原料碳酸亚铁并回收铜。
99里面有____个十和____个一。