1. experiment: v. to try various ideas, methods etc to see whether they will work or what effect they will have 试验;试用
2. skyscraper: n. [C]a very tall modern city building 摩天大楼
3. identical: adj. exactly the same 完全相同的[+to]
4. capture: v. to succeed in showing or describing a situation or feeling using words or pictures(用语言或图片)记录下
5. retouch: v. to improve a picture or photograph by painting over marks or making other small changes描绘，润色(图画、照片)
You may remember that a few weeks ago we discussed the question of what photography is. Is it art, or is it a method of reproducing images? Do photographs belong in museums or just in our homes? Today I want to talk about a person who tried to make his professional life an answer to such questions. Alfred Stieglitz went from the United States to Germany to study engineering. While he was there, he became interested in photography and began to experiment with his camera. He took pictures under conditions that most photographers considered too difficult. He took them at night, in the rain, and of people and objects reflected in windows. When he returned to the United States he continued these revolutionary efforts. Stieglitz was the first person to photograph skyscrapers, clouds, and views from an airplane. What Stieglitz was trying to do in these photographs was what he tried to do throughout his life: make photography an art. He felt that photography could be just as good a form of self-expression as painting or drawing. For Stieglitz, his camera was his brush. While many photographers of the late 1800's and early 1900's thought of their work as a reproduction of identical images, Stieglitz saw his as a creative art form. He understood the power of the camera to capture the moment. In fact, he never retouched his prints or made copies of them. If he were in this classroom today, I'm sure he'd say, "Well, painters don't normally make extra copies of their paintings, do they?"