贵州流域面积在10000平方千米以上的河流下列有：（）。

A、赤水河

B、綦江

C、珠江

D、乌江

The boss took it for granted that his secretary should keep him well-informed.

A．assumed that it was true without doubt

B．believed that it was true without making sure

C．agreed that it was necessary

D．thought that it was beneficial