单选题 To understand what we are going to talk about today, you have to rely on what you have read previously.
  • A. beforehand
  • B. carefully
  • C. before
  • D. in advance


【正确答案】 C
【答案解析】[解析] previously和before都表示“以前、从前”；beforehand和in advance意思相同，都“事先、预先”；carefully：仔细地。