篇一: Dear David, Im glad to receive your letter. I have learned from your letter that you are concerned about the smog which frequently appears in some areas of China. Thank you for your concern. Im also very worried about such terrible...
篇一: Dear David, Im glad to receive your letter. I have learned from your letter that you are concerned about the smog which frequently appears in some areas of China. Thank you for your concern. Im also very worried about such terrible...