长江、黄河都流经的省级行政区和地形区是：[ ]

A．青海、四川和青藏高原

B．青海、甘肃和黄土高原

C．青海、西藏和青藏高原

D．四川、甘肃和柴达木盆地

The microscope opened up to man another strange new world: a world of things too near and small for anyone () the scientist to know much about or do much about.

A. besides

B. apart from

C. but

D. without