阅读理解。 An old friend from California called from the airport to tell me that he had arrived. I was not able to leave the office, but I had made plans for his arrival. After explaining where my new house was, I told him that I had left the key under the doormat (门前的擦鞋垫). Since I knew it would be quite late before I could get back, I suggested that he make himself at home and help himself to anything that was kept in the refrigerator (冰箱). Two hours later my friend phoned me from the house. At the moment, he said, he was listening to some of my records after having had a nice meal. He had found the pan and meat in the refrigerator. Now, he was drinking a cup of tea and hoped that I would join him soon. When I asked him if he had any difficulty finding the house,he answered that the only problem was that he had not been able to find the key under the doormat, but luckily, the living room window by the apple tree had been left open and he had climbed in through the window. I listened to all this in great surprise. There is no apple tree outside my window, but there is one by the living room window of my next-door neighbor's house! 1. When my friend arrived,I could not go to meet him because _____. [     ] A. we were not good friends B. I was busy at work C. he had not told me that he would come D. I did not want to see him 2. I listened to my friend's phone call in great surprise because _____. [     ] A. he had not waited for me to eat together B. he had eaten too much of the food C. he mistook my neighbor's house for mine D. he had left the house with the window open 3. In fact my friend _____. [     ] A. did not enter my house B. entered my house after he opened the door C. entered my house by climbing through the window D. entered my house with the help of my neighbor 4. The writer left the key under the doormat so that _____. [     ] A. nobody would find it B. he might not lose it C. his family could use the same key D. his friend could easily get it