单选题 The letter of thanks seemed ______ already for I found it on the writing table just now.
  • A. to have written
  • B. wrote
  • C. written
  • D. to have been written
【正确答案】 D
【答案解析】[解析] 这是一个动词不定式的被动语态。它的构成是：to+be+done。