下列物质中属于纯净物的是( )
A:Na2CO3·10H2O
B:水泥
C:纯净的盐酸
D:普通玻璃
2013年5月,质检部门发现了“有毒镉大米”。根据镉在元素周期表的信息可知( )
—Did you have fun _____________ on your last day off?
—No, I didn't. there were too many people and it was really crowded.