自工业革命以来，人类大量焚烧化石燃料和毁林，排放的温室气体不断增加，导致了20世纪全球明显升温。如果要控制大气中温室气体浓度的长期增长，各国就要进行人为干预，或者从源头上限制化石能源的使用，减少温室气体排放；或者增加温室气体的排放，即通过植树造林把排放到大气中的温室气体重新吸收起来。 据此，可以推出( )。
A．如果从源头上限制化石能源的使用，就能避免全球明显升温
B．如果通过植树造林增加温室气体的排放，就能避免全球明显升温
C．如果各国既不从源头上限制化石能源的使用，又不增加温室气体的排放，就不能控制大气中温室气体浓度的长期增长
D．如果各国从源头上限制化石能源的使用或通过植树造林增加温室气体的排放，就能控制大气中温室气体浓度的长期增长
参考答案：C
解析： 若原命题为真命题，原命题的逆否命题也为真命题，由“如果要控制……，就要……”推出其逆否命题为“如果不……，就不能控制”，C项是题干的逆否命题，C项正确。故选C。
① On Friday, January 14, 2005, my cousin, Kara Rose, came into the world. ② She looked perfectly healthy from the outside, but on the inside, the doctors had failed to discover a serious problem. ③ She often had trouble breathing and then turned blue. ④ The doctors found that Kara had been born without part of her heart. ⑤ They didn’t think she would live long enough to leave the hospital. ⑥ When she was four days old, she had her first operation. ⑦ My family stayed together during this hard time, hoping everything would turn out for the best. Kara’s strength and determination to live were strong. Eventually, she could go home. We all waited patiently for new technology that could give Kara a new heart. When she was eighteen months old, her parents took her to a famous surgeon who performed a series of operations. There was no guarantee she would make it through the operation, but she succeeded. Kara grew stronger every day, and it was not long before she was well enough to be around people. She had an amazing character and always wore a sweet smile. When she fell asleep against my body, happy and content, I realized how valuable life really is. As I took her in my arms with her warm breath against my neck, I decided to live every day of my life to the fullest. This child, who is 15 years younger than I, has gone through more suffering and pain than I ever have. I admire her strength and determination. Kara has taught me that no matter how bad things seem, they can work out in the end. Knowing this small, beautiful child has made me a stronger person, I now believe that difficulty can be beaten. 小题1:Kara often had trouble breathing because ________.
小题2:Which of the following statements is true?
小题3:The writer wants to tell us that _______.
小题4:Where should the sentence in the box be added in Paragraph 1?
C. After Sentence ⑤. D. After Sentence ⑦. |