B. The cause of allergic reactions has not been determined.
C. The nervous system balances allergic reactions.
Chọn B
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Exercise 1. Complete each of the following sentences with the correct answer (A, B, C or D). Identify your answer by writing the corresponding letter A, B, C or D on your answer sheet.
Millie’s father accused her of _________.
Choose the word whose stress pattern is different from the other three in the following questions