单选题 If you want to do well on the exam, you ______ on the directions that the professor gives and take ex-act notes.
  • A. will have concentrated
  • B. have to concentrate
  • C. will be concentrated
  • D. will be concentrating
【正确答案】 B
【答案解析】[解析] 用一般现在时，不用虚拟语气。答案是B。