核心语法结构 — 英语阅读题

Read the following passage and answer the question. Last semester, Li Hua joined our English study group. Having failed the CET-4 exam twice, he decided to change his learning methods. Instead of memorizing word lists mechanically, he began reading short articles every morning. The vocabulary book that he bought at the campus store turned out to be very helpful. By the end of the term, he had made remarkable progress, and his classmates, impressed by his improvement, asked him to share his experience. He told them that only by practicing regularly could anyone expect to pass the exam. Question: In the sentence "Having failed the CET-4 exam twice, he decided to change his learning methods," the perfect participle "Having failed" is used because ______. A. the action of failing happened before the action of deciding B. the subject "he" is unknown to the readers C. the two actions happened at exactly the same time D. the word "decided" must always be followed by a participle