Policemen used tear gas to ________ a demonstration of black high school students today.
A.break through
B.break up
C.break into
D.break off
网友回答
B解析四个选项的短语动词意思分别为：break through突破，冲垮；break up打碎，驱散，解散；break into闯入；break off折断。句意：今天，警察使用了催泪弹来驱散黑人中学生的示威。