Each request carries some data over the network; if the request does not find any updates on the server, this data transfer is a waste.

每一次请求都要在网络上传输一些数据；如果请求未在服务器上发现任何更新，那么这个数据传输就是浪费的。

youdao

On the top of that, each request carries some data over the network; if the request does not find any updates on the server, this data transfer is a waste.

除此之外，每一次请求都要在网络上传输一些数据，如果请求未在服务器上发现任何更新，那么这样的数据传输就是浪费资源。

youdao

Consider the case of a program sending a purchase request to another program over a network.

考虑一下这种情况：一个程序通过网络向另一个程序发出一个购买请求。

youdao

The time taken for this round-trip of request and acknowledgment determines the network's latency.

ECONOMIST: The faster the internet becomes, the slower it loads pages

Al-Zindani denied CNN's request for an interview but allowed the network to tape at the school he's built from the ground up since the early 1990s.

CNN: Yemen university in focus after Christmas jet incident

For instance, with two clicks, The Resumator allows its customers to post their jobs to Facebook, LinkedIn or Twitter and request referrals from specific people in their network.

FORBES: Social Hiring Tools Used By Hyper Growth Companies: Pinterest, Tumblr, HootSuite, Klout, Posterous, Bitly And Mashable