______, so he stopped the car at once.

A．Seeing a boy lying on the road

B．On seeing a boy sitting on the road

C．The driver had seen a boy standing on the road

D．The minute the driver saw a boy seated on the road

九寨沟、黄龙等景区属于世界遗产项目的______类。

A．文化遗产
B．自然遗产
C．文化与自然双遗产
D．文化景观