What we know about certain diseases are still not sufficient to prevent them from

45/80

Mark the letter A, B, C,or D on your answer sheet to show the underlined part that needs correction.
What we know about certain diseases are still not sufficient to prevent them from spreading easily among the population.

What we know about

are

from spreading

among

Giải thích

Đáp án là B. are => is. Với mệnh đề danh ngữ “ What + S+ V” đứng đầu câu làm chủ ngữ, động từ sẽ chia ở dạng số ít.