TOEFL Listening: ETS-TOEFL听力机经 - X1EVMJ05317L0YE6P$

What was William Talbot's major contribution to the development of photography? A. A way to make paper sensitive to light. B. A device that gives photographers precise control of exposure times. C. A process for printing images on objects such as leaves. D. A process for producing photographs from a negative image.