What has brought about unbelievable advancement of the global economy in the latest 20 years?

The time he has devoted in the past years __________ the disabled is now considered __________ of great value.

Over the past 20 years, the Internet has helped change our world in way or another for the better.

The agent has probably already handed over you the stowage plan，（）.

Compared with last year, the output of the factory this year has increased（）20%.

For years, Gerardo Jerry Jimenez has been helping the kids suffered from domestic violence.____

【A popular service that has attercted the interest of companies and has home users alike is the sending of voice signals over an IP-based network, such as the Internet. The practice of making telephone calls over the internet has had a number of different names, including packet voice, voice over packet, voice over the internet, internet telephone, and Voice over Ip（Voip）. But it appears the industry has settled on the term”Voice ove IP” in reference to the internet protocol, which controls the transfer of data over the internet. There are currently three ways to deliver VoIp to users, the first technique is found at the corporate level. Many companies are offering VoIP systerms that operate over a local area network. These systems involve a fair amount of equipment, such as VoIP servers, special IP-enabled telephones, and routers that can direct telephone calls. Today a large portion of corporate sites have converted their older internal telephone systems to VoIP systems that opreate over a LAN, thus converging two systems into one. A second common solution is the one often encountered at home. Using existing telephones, a special converter is added between the telephone and a high speed internet（DSL or cable modem）connection. The converter digitizes the voice signal and creates a stream of packets that are then sent over an ip connection.The third technique involves smart cell phones. Never cell technologies are all packet-based, thus requiring a telephone call to be converted to digital packets and sending those packets over IP networks.】

During the past ten years, there have been_____changes in the country.

Over the past ten years, natural gas production has remained steady, but _____ has risen steadily.

Mr.Joe has worked very hard in the past two years and has paid all his debts_________ the last penny.

Over the past 20 years, the Internet has helped change our world in either way or another for the better.