选词填空 根据短文内容,从方框中选出恰当的单词或短语填空,使语意通顺完整。每个选项只能用一次, 有两项剩余。请将答案标号写在答题纸相应的横线上。A. worried B. less C. spends D. fold E. Secondly F. provide G. turns on H. little I. with J. anyone K. alone L. lonely Dear Abby, I’m a helpless mother of a teenage boy. My son is going to be 15 this summer. He used to help me 1 the clothes or do the dishes at home. But I find that 一株C3和一株C4植物被放在同一钟罩下,与外界空气隔绝,每天照光12小时,二星期后C3植物死亡,因为A.C4植物在夜间呼吸需氧较少B.C4植物比C3植物更高等C.C3植物光能利用率低D.C4植物固定CO2的能力强