Directions: For each blank in the following passage there are four words or phrases marked A, B, C and D. Fill in each blank with the word or phrase that best fits the context.
When I was 8 years old, I once decided to run away from home. With my suitcase 1 and some sandwiches in a bag, I started for the front door and said to Mom, “I'm leaving.”
“If you want to 2, that's all right,” she said. “But you came into this home without anything and you can leave the same way.” I 3 my suitcase and sandwiches on the floor heavily and started for the door again.
“Wait a minute,” Mom said. “I want your 4 back. You didn't wear anything when you arrived.” This really angered me. I tore my clothes off—shoes, socks, underwear and all—and 5, “Can I go now?” “Yes,” Mom answered, “but once you close that door, don't expect to come back.”
I was so 6 that I slammed (砰地关上) the door and stepped out on the front porch. 7 I realized that I was outside, with nothing on. Then I noticed that down the street, two neighbor girls were walking toward our house. I ran to 8 behind a big tree in our yard at once. After a while, I was 9 the girls had passed by. I dashed to the front door and banged on it loudly.
“Who's there?” I heard.
“It's Billy! Let me in!”
The voice behind the 10 answered, “Billy doesn't live here anymore. He ran away from home.” Glancing behind me to see if anyone else was coming, I begged, “Aw, c'mon, Mom! I'm 11 your son. Let me in!”
The door inched open and Mom's smiling face appeared. “Did you change your 12 about running away?” she asked.
“What's for supper?” I answered.
（a＞0，b＞0）的一条渐近线为
，离心率
，则双曲线方程为