多次交换 meaning in Chinese

multiple exchanges

For a business combination realized by two or more transactions of exchange , the combination costs shall be the summation of the costs of all separate transactions
（二）通过多次交换交易分步实现的企业合并，合并成本为每一单项交易成本之和。
If an http client and server expect to exchange data multiple times in a short time period , a persistent connection speeds up their communications by allowing them to avoid the overhead required to open and close a tcp connection for each message
如果某个http客户端与某个http服务器预期在一段短时间内多次交换数据，则持续型连接将使双方可以避免为每条消息打开和关闭tcp连接所需的系统开销，从而加速双方的通信。