(Viên chức Mầm non) bài tập tiếng Anh theo chủ đề có đáp án - Test 1
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Since the 1930‘s chemical insecticides such as d. D. T_________ very effective in destroying disease-carrying insects.

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Since the 1930‘s chemical insecticides such as d. D. T_________ very effective in destroying disease-carrying insects.

proved

was proved

has proved

have proved

Giải thích

Đáp án đúng là d