to have the information, knowledge, etc. that is needed in a particular situation and be able to find it easily and use it quickly掌握（信息等）；熟悉，精通（知识等）；对…了如指掌；有…随时可供使用
I made sure I had all the facts at my fingertips before attending the meeting.在参加会议之前，我确保掌握了所有的事实。