问题
选择题
幻灯机能把幻灯片上的景物的像变成放大的实像。这时幻灯片到镜头的距离u为[ ]
A、u＞2f
B、2f＞u＞f
C、u＜f
D、u＝2f
答案
答案：B
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幻灯机能把幻灯片上的景物的像变成放大的实像。这时幻灯片到镜头的距离u为[ ]
A、u＞2f
B、2f＞u＞f
C、u＜f
D、u＝2f
答案：B
| 完型填空。 | |||
| Mr. s Green lives in the country (乡村), and she doesn't know London very well. One day, she goes to London. She can't find her __1__. Just then she __2__ a man near a bus stop. "I can ask him the way," she says to __3__ and asks," Excuse me, will you please __4__ me the way to King Street?" The man smiles with __5__ answer. He __6__ know English. He speaks Russian. He is a visitor. Then he __7__ his hand into his pocket (口袋), __8__ a piece of paper and lets her __9__ it. On the paper are these words, "Sorry, I __10__ English. | |||
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