37. James R. Ehleringer tried to find out
  A if our bodies break water down into its parts.
  B if it is possible to collect hair samples across the country.
  C if tap water contains unique proportions of isotopes of hydrogen and oxygen.
  D if the composition of hair can indicate exactly where people are from.
  38. Which of the following statements is meant by the writer?
  A Ehleringer was successful in his research.
  B Ehleringer failed in his research.
  C Ehleringer can be a successful detective.
  D Ehleringer's research proved successful in China.
  39. What does the last paragraph tell you?  A The new technique can tell precisely where a person lives.
  B Water supplied in different regions all come from the same source.
  C Types of water used in different regions provide useful information for the police.
  D Hair samples provide the most important clues to identify crimes.
  40. Which of the following is closest in meaning to the title?
  A Human hair may help detectives to solve crimes.
  B Animal hair may help detectives to solve crimes.
  C Detectives watch hairy criminals closely.
  D Most detectives are hair specialists.