Inthe1940sclassroomviolence______A．wassomethingunhear

In the 1940s,classroom violence______.

A．was something unheard of

B．was by no means a rare occurrence

C．attracted a lot of public attention

D．began to appear in analysts\” data

正确答案：A
确切地说该题属例证题依据文章第五段第三行“unheardofinthe1940s”