29. Why does the author mention contact tracing in the third paragraph?
(A) To illustrate why vaccine development is unnecessary
(B) To explain how governments collect economic data
(C) To emphasize a major difficulty in controlling the outbreak
(D) To show that most infections occur outside Africa

答案：登入後查看
統計： 尚無統計資料

詳解 (共 1 筆)

#7564950
測驗目標 本題屬於閱讀測驗——寫作目的題...
(共 1013 字，隱藏中）
前往觀看
0
0