题干

以前,人们往往认为一切生物的生长都依赖阳光。现在科学家发现,在水深超过4000米的可见光不能到达的海底,在高温、高压、剧毒、缺氧的环境里,仍然存在大量海底热液生物,它们靠海底热液带出的能量进行化合作用合成有机质而生存。这从一个侧面表明(        )

①对真理的追求是永无止境的循环过程     

②真理是理论与实践的具体的历史的统一

③客观事物的复杂性决定了认识的反复性   

④认识只有不断超越历史条件才能成为真理

A:②③

B:①④

C:①②

D:③④

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答案(点此获取答案解析)

A

同类题1


Tony and Jane give their opinions about keeping pet dogs.

  Keeping pet dogs is a good idea, says Tony 

       I think people should be allowed to keep pet dogs. There are lots of reasons for this.

       First, dogs are really cute. It's nice to pick them up and hold them in our arms, and it's wonderful to see them growing up quickly.

       Second, your dog might not be dangerous but by simply barking(吠)he can keep away a burglar(窃贼)who might think of entering your house.

       Finally, we can also learn about life and death from dogs. Young people can learn how to care for others and how to respect(尊重)all living things by keeping a pet dog.

     I think keeping pet dogs is something everyone can enjoy.

      Keeping pet dogs is not a good idea, say Jane

      In my opinion, it is never a good idea to keep a pet dog.

       Firstly, pet dogs creates a lot of mess. They leave fur(毛) and hair on the floor, on beds and on sofas, and they need to be washed daily.

       Secondly, we should remember that not all dogs are friendly. Some dogs bark at people they do not know. A few dogs bark all night. This stops their neighbors from getting any sleep. A small number of pet dogs even bite(咬) people.

       Lastly, you have to make sure pet dogs are in good health and provided with good pet products. Paying for dog food and visiting the vet when dogs are ill can be expensive.

       I believe that people should not keep pet dogs.