Who holds a critical view on economists‘ role in medical field according to the passage？
Amartya Sen.
B. Jeff Sachs.
C. Larry Summers.
D. Clare Chandler.
Why did their friends react so negatively to their plan about their trip？
A. They thought their lives might be endangered.
B. They thought their plan was not prudently made.
C. They believed that the tourist areas were peculiar.
D. They believed that the people in the tourist areas were eccentric.
Sip and zip， tip and dip， mop and nap are all__________.
A. minimal pairs
B. diphthongs
C. allophones
D. phonemes
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