Đáp án B
Trong đoạn 1, từ “arduous” gần nghĩa _______.
A. liên tục
B. khó khăn
C. cụ thể
D. chi tiết
According to the passage, what is the most common source of lead poisoning in children?
Which of the following gives the main idea of the third paragraph?
Why does the author mention "artistic, political, or pedagogic communication" ?
The word “viable” in paragraph 4 could be best replaced by ________.