Answer

31.2
1 There's interesting PhD theses on water resources in the library.
2 What was your main criterion in designing your survey?
3 She was interested in a strange phenomenon connected with comets.
4 The hypotheses were never proved, as the data were incomplete.

31.3
1 We must never accept the notion that intelligence is connected to race.
2 The task of choosing an analytical framework is an important stage in any research.
3 The book expresses his viewpoint on the role of the United Nations in times of war.
4 Tannen has always made her stance on gender and language use very clear.
5 Consumers have different perceptions of what low price and high quality mean.
6 The report laid out a new model of dark matter to explain certain observations.
7 Physicists developed the concept of family healthcare which changed everything.