Mark the letter A, B, C, or D on your answer sheet to indicate the word or phrase that is OPPOSITE in meaning to the underlined part in each of the following questions
Population growth rates vary among regions and even among countries within the same region
A. fluctuate
B. stay unchanged
C. restrain
D. remain unstable
Đáp án : B
Vary = đa dạng, thay đổi phong phú. Stay unchanged = giữ ở tình trạng không đổi