To understand the grammar of the sentence you must break it into parts.A. upB. downC. off

问题补充：

To understand the grammar of the sentence，you must break it into parts.

A. up

B. down

C. off

D. out

答案：

A. up

(答案→)B. down

C. off

D. out

解析：

试题分析:考查动词短语。break up“学校放假，驱散人群”；break down“分解，机器坏掉”；break off“终止，这段”；break out“爆发”。根据句意可知B选项正确。句意：为了理解句子的语法，你必须要把它拆分成若干部分。