— Jim took one-hour ride just now. What a short time he spent finishing such a long way!— He is experienced rider.
A:an; the
B:an; a
C:a; an
D:a; the
下列物质属于纯净物的是 ( )
将两个高锰酸钾颗粒分别放入温度不同的两杯清水中,温度较高的那杯冰先变红,这一现象说明( )
“一朝步入画卷,一日梦回千年。”穿越时空来到宋代,我们不能做到的是( )