Wireshark-dev: [Wireshark-dev] why is the ack number of several ack frame in tcp transmission i

From: "??????????" <237825552@xxxxxx>
Date: Mon, 7 Apr 2014 21:33:08 +0800
why is the ack number of several ack frame in tcp transmission the same?Is that the ack of several tcp segments?if so,how to calculate the bytes of data that been received every time?