题干

如图A、B、C、D、E为初中常见的物质,它们的转化关系如图所示(“→”表示反应生成),按要求完成下列问题(有关反应条件已省略).

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同类题3

阅读下面短文, 从短文后各题所给的四个选项(A、B、C、D)中, 选出可以填入空白处的最佳选项。

    The day finally came, when I had to leave the warm home where I'd grown up. I ran to the back yard, as tears came up from my heart. Suddenly I 1 a hand rest on my shoulder. I looked up to 2  my grandfather. “It isn't 3 , is it, Billy?” he said softly.

    He gently 4  my hand in his, and then we walked, hand in hand, to the front yard, 5 a huge red rose-bush sat alone.

    “What do you see here, Billy?” he asked. I looked at the flowers, not knowing 6  to say, and then answered, “I see something soft and 7 ,  Grandpa.”

    He pulled me 8 . “It isn't just the roses that are beautiful, Billy. It's that special place in your heart that makes them so.” “Billy, I 9 these roses when my first son was born. It was my 10  of saying ‘thank you' to God. I 11 to watch him pick roses for his mother. Then, as a young man of only 20, a terrible war robbed him of his life.” Grandpa slowly stood up. “Never say good-bye, Billy. Never 12  to the sadness and the loneliness. Instead, I want you to remember the joy and the 13  when you first said hello to a friend.”

    A year later, my grandpa became very 14 . Then all members of the family were 15  back, and I returned to the old house. When it came to my 16 , I took his hand as 17  as he had once taken mine.

    “Hello, Grandpa,” I 18 . His eyes slowly opened and said, “Hello, my friend.” With a brief (短迅的) 19  he died. Suddenly, and truly, I knew what he had 20  about never saying good-bye — about refusing to give in to sadness.