I made sure I had all the facts_ my fingertips before attending the meeting29/50Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions. I made sure I had all the facts__________my fingertips before attending the meeting. withat by forGiải thíchĐáp án B. Ta có cụm từ: At one’s fingertips: trong tầm tay