A polite way of telling someone you haven't heard a word they said. Commonly used on long conference calls, when the speaker is monotonous, boring, or couldn't make a point of one were drawn for them. ... Joe: "Blah, blah corporate office blah, blah, leverage proactively blah, blah human capital and grade-A synergy, blah, blah. Do you agree, Jim?"
Jim: "I'm sorry, Joe, I was multitasking, can you repeat that?"

Note:

Multitasking的意思是多任务处理的，你可以用它来形容你很忙，是没听见别人说话的好借口，一般用于冗长的会议。例如会议很无聊，发言人大篇幅发言后突然问你有何感想，你可以说I was multitasking，能重复一遍么？