________in the qucue for half an hour ,the old man auddenly realized he had left the cheque in the car.

A．Waiting

B．To wait

C．Having waited

D．To have waited

今年“十一”长假期间，我市某景区在10月3日接待游客约2.83万人，“2.83万”可以用科学记数法表示为[ ]

A．0.283×10⁵

B．2.83×10⁴

C．28.3×10³

D．283×10²