The system has been in operation for six months.
這個系統已經執行六個月了。
The company has been investing in new plant and equipment.
這家公司一直在投資購置新機器和裝置。
A new system has been devised to control traffic in the city.
控制城市交通的'新系統已經設計出來。
Digital television has been around for some time now.
數字電視已經面市一段時間了。
A new advance has been made in the control of malaria.
在控制瘧疾方面已取得新的進展。