It is implied in Paragraph 2 that years ago governments _____.

A. paid much attention to the results of scientific discoveries
B. seldom introduced safety laws before disasters occurred
C. hardly ever looked into the causes of tragedies
D. imposed safety rules as soon as disasters occurred
A. paid much attention to the results of scientific discoveries
B. seldom introduced safety laws before disasters occurred
C. hardly ever looked into the causes of tragedies
D. imposed safety rules as soon as disasters occurred

【答案】