单选题 When I reached London, it had one of the thickest fogs in years. I could hardly see my hand in front of my face; cars and houses ran very slowly with their lights on. When evening fell (落下；下降), it got worse (更坏的，更差的).All traffic (交通) came (来，出现) to stop. Because I had an important meeting on the other side of Lon-don, I had to walk.
Minutes later (后来，过一会儿), I was lost. Then I heard a young woman' s voice (声音，发言权) out of the fog. "I think you are lost. Can I help you?" I could hardly see her, but I was very glad to find another person out in the fog. I told her where I wanted to go and she said she knew very well how to get there.
When I walked after her through the streets, I said "How can you find the way so easily (容易地)?" "I know this part of London very well," she answered. "But in so thick (厚的，浓的) a fog it's hard to see anything," I said.
"With the fog or without the fog, it makes no difference (差异) to me. You see, I'm blind (瞎的，盲目的)," she answered.