“绿叶在光下制造淀粉”的实验中，把天竺葵放到黑暗处一昼夜的目的是（ ）
A．降低温度
B．使叶片中的淀粉耗尽
C．增加叶片温度
D．减弱植物体内物质的运输
为保证天竺葵叶片内的淀粉是新制造的，必须把贮存的淀粉运走或耗尽．把天竺葵放到黑暗处，天竺葵不能进行光合作用，呼吸作用仍在进行，淀粉等有机物不断地被分解，直至耗尽．A、C、D不符合题意，B符合题意．
故选B．
On this Christmas Day I had the wonderful opportunity to see the true spirit of Christmas. My big family always ____ presents together at the start of the New Year and have done so in this way for more than 40 years. Since the beginning, my grandfather and grandmother have ____ their children and cousins on this day in their small farmhouse. With 13 ____ and uncles and more than 30 cousins in this group, there were usually more than 50 people in the room to exchange gifts. Because of the activity, the flying wrapping paper, so many people and the limited space of a 65-year-old farmhouse living room, most of the individual moments went ____. My nephew, Jack (9 year old), who was walking by my 5-year-old cousin, Seth, in the Christmas chaos, noticed that Seth was crying. Jack ____ to ask him what was wrong and why he was crying. Seth ____ that he didn’t receive any toys! Almost without _____, Jack looked down to the only two toys he had received, and _____ Seth with his best toy! He said, “Here, you can have this one. I don’t have to have it. I have other toys I can play with at home.” Tears were welling up in my eyes! I was moved by this huge act of _____. I was so _____ of my nephew and what he had done when he thought no one else was looking. I gave him a huge _____ and told him that he had demonstrated(演示) the true _____ of Christmas!
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