76. As the 1st paragraph implies, there is between environmentalists and mainstream society ____.

1. a misunderstanding
2. a confrontation
3. a collaboration
4. a consensus

77. Within the planetary boundaries, as Rockstrom implies, ____.

1. we humans have gone far beyond the limitations
2. our human activities are actually moderate in degree
3. a certain level of human impact is naturally acceptable
4. it is urgent to modify our relationship with the environment

78. The point, based on Rockstrom's investigation, is simply that ____.

1. they made the first classification of Earth systems
2. it is not to deny but to manage impacts on the planet
3. we are approaching the anthropogene faster than expected
4. human being s are rational and responsible creatures on earth

79. Critical of the IPCC's 2007 report, the author argues that they ____.

1. missed the most serious problem there
2. were poorly assembled for the mission
3. cannot be called scientists at all
4. value nature above people

80. It can be concluded from the passage that if we are to manage the anthropogene successfully, we ____.

1. must redefine our relationship with the environment
2. should not take it seriously but to take it easy
3. need a new way of thinking about nature
4. need cooler heads and clearer statistics

(Reference keys.)