(Viên chức Mầm non) 1128 câu trắc nghiệm Tiếng Anh A2 có đáp án - Phần 15

Once an offending allergen has been identified........... tests, it is possible for the doctor to give specific desensitizing injections.

17/30

Once an offending allergen has been identified........... tests, it is possible for the doctor to give specific desensitizing injections.

means of

of the means by

by means of

by means

Giải thích

Chọn đáp án C