阅读下面短文，从短文后各题所给的A、B、C和D四个选项中，选出可以填入空白处的最佳选项。
In spite of the fun and laughter, 13-year-old Frank Wilson was not happy. It was 1 that he received all the presents he wanted. And he also 2 the big Christmas dinner with family members.3, Frank was not happy because this was his first Christmas without his brother, Steve, who during the year, had been killed in a car accident. Frank 4 his brother.
Frank said good-bye to his relatives, and explained to his parents that he was going to see a friend. Since it was cold outside, Frank 5 his new plaid jacket. It was his favorite gift. He placed the other presents on his new sled (雪橇). Then Frank 6.
As Frank went down the street toward home, through one front window, he saw a room with old 7 hanging over an empty fireplace. A woman was seated nearby, crying. The stockings 8 him of the way he and his brother always 9 theirs side by side. The next morning, they would find presents.
Then Frank had a10. He knocked on the door. “Yes?” the 11voice of a woman asked. “May I come in?” asked Frank. “You are very welcome,” she said.12his sled full of gifts and thinking he wanted to 13 gifts. “But I have no food or gifts for you. I have 14 for my own children.” “That's not why I am here,” Frank replied. Please 15 whatever presents you would like for your children from the sled.” “Why, God bless you!” the 16 woman answered gratefully. She selected some candies, a toy airplane and a doll. Finally, the stockings were 17. “Thank you so much!” the woman Said. “You are welcome,” Frank said and left.
Frank's18was full of happiness. Then he gave his jacket to a poor boy. At last, he19 all his gifts. Now Frank was worried how he could 20 to his parents that he had given his presents to others.
2HI(g)。已知H2和I2的起始浓度均为0.10 mol·L-1，达平衡时HI的浓度为0.16 mol·L-1。若H2和I2的起始浓度均变为0.30 mol·L-1时，则平衡时H2的浓度（mol·L-1）是