52. What does the underlined word "centenarians" in Paragraph 1 refer to?
A、People who have secret lifestyles.
B、People who enjoy physical exercise.
C、People who are one hundred years old or older.
D、People who carry the gene for being slim.
49. According to Bryk and Schneider, what was most important for successful school improvemt?
A、New standards and tests in schools.
B、Positive social relationships.
C、Strict teacher and student evaluations.
D、Assistance of the government.
I.Phonetics ( 5 points)Directions:In each of the following groups of words, there are four underlined letters or letter combinations marked A, B, C and D. Compare the underlined parts and iden-tify the one that is different from the others in pronunciation. Mark your answerby blackening the corresponding letter on the Answer Sheet.