现代大学英语精读3lesson8 we are only human 课文paragraph

1.I do for you because I can expect some reciprocal benefits in the future. (para. 6, lesson 8)
I do for you for the reason that I hope you to do for me in return in the future.

2.There is seemingly no biological benefit to acting with conscience; if there were, only moral individuals would survive and procreate. (para. 30, lesson 8)
It seems that doing things with conscience will be no good. If there were any benefits, only people with moral senses would live and develop.

3. survival of the fittest (lesson 8)
Who fits the surroudings most will survive.

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