Thanks very much for your story. The plot is very touched. Now listen to me carefully. It’s very funny. One day, a young man was going from house to house on the street so he wanted to introduce him to all his new neighbors. Outside one house, he stopped and saw a big dog sitting on the sidewalk. Well, he thought that it was belonged to the people in the house, but he paid no attention to it. He just pressed the bell, and the owners asked him in, and the dog went in, either. He greeted them with a smile and then he sat down, and a couple gave him a cup of coffee and some cookies. Well, the dog ate one of the cookies off the plate, and sat in his knee. The young man don’t want to seem rude, so he petted the dog gentle and continued talking to the couple. Anyway, gently when it was time to go, he thanked them and left. When the young man left, the woman called after him, “Excuse me, don’t forget to take your dog!

人体能引起振动觉有频率为（）。人体对（）左右的振动最敏感。眩光源对视觉效率的影响与视线和眩光源的（）有关。