A:铝
B:镁
C:铁
D:钙
They are looking forward to an exciting vacation.
She ____ ____ the customers' complaints ____ every time.
小张的爷爷每天坚持体育锻炼,星期天爷爷从家里跑步到公园,打了一会太极拳,然后沿原路慢步走到家,下面能反映当天爷爷离家的距离y(米)与时间t(分钟)之间关系的大致图象是( )