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TOEFL
/
Listening practice
/ Section TZ4A
Listen to an Academic Talk
Listen to part of a talk in an immunology class.
Listen
25. What is the talk mainly about?
A
Why early transfusions were technically difficult to perform
B
Why blood cannot be stored for long periods
C
How antibodies are produced in the body
D
How a missing idea, rather than a missing technique, held back transfusion