The city of Venice，in Italy，is one of a kind．It is built on more than 120 islands，just off arrival．After explaining where my new house was，I told him that I had left the key under the doormat．Since I knew it would be quite late before I could get back，I suggested that be 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 bad 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！
46．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
47．A doormat is a mat______．
A．used as a door B．for cleaning the bottom of shoes
C. put up on a door as an ornament（装饰物）
D．near a door under which people put their keys
48．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
49．At last 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
50．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