The iPhone is a line of smartphones designed and marketed by Apple Inc. It runs Apple's iOS mobile operating system, known as the 'iPhone OS' until mid-2010, shortly after the release of the iPad. The first generation iPhone was released on June 29, 2007, the most recent iPhone, the seventh-generation iPhone 5S, on September 20, 2013. The user interface is built around the device's multi-touch screen, including a virtual keyboard. The iPhone has Wi-Fi and cellular connectivity (2G, 3G, 4G, and LTE). An iPhone can shoot video (though this was not a standard feature until the iPhone 3GS), take photos, play music, send and receive emails, look through the web, send texts, and receive visual voicemail. Other functions—games, reference, GPS navigation, social networking, etc.— can be enabled by downloading apps; as of 2012[update], the App Store offered more than 775,000 apps by Apple and third parties. There are six generations of iPhone models, each accompanied by one of the six major releases of iOS. The original 1st generation iPhone was a GSM phone, and established design precedents, such as a button placement that has persisted through all models and a screen size maintained until the launch of the iPhone 5 in 2012. The iPhone 3G added 3G cellular network capabilities and A-GPS location. The iPhone 3GS added a faster processor and a higher-resolution camera that could record video at 480p. The iPhone 4 featured a higher-resolution 960 × 640 'retina display', a VGA front-facing camera for video calling and other apps, and a 5-megapixel rear-facing camera with 720p video capture. The iPhone 4S upgrades to an 8-megapixel camera with 1080p video recording, a dual-core processor, and a natural language voice control system called Siri. IPhone 5 features the new A6 processor, increases the size of the Retina display to 4 inches, and replaces the 30-pin connector with an all-digital Lightning connector. The resounding sales of the iPhone have been credited with reshaping the smart phone industry and helping make Apple one of the world's most valuable publicly trading companies in 2011–12. However, there has been criticism of the company's outsourcing and move of jobs from the US to China. Apple and its manufacturing contractor Foxconn have received criticism due to poor working conditions at the assembly plant in China. 小题1:An iphone is from __________. A．the USA B．South Korean C．the UK D．Australia 小题2:What is the newest kind of iphone at present? A．iphone 4 B．iphone 4S C．iphone 5 D．iphone 5S 小题3:How many generations of iphone models are there now? A．Five B．Six C．Seven D．Eight 小题4:What are the features of iphone 5? A．The new A6 processor B．increases the size of the Retina display to 4 inches C．replaces the 30-pin connector with an all-digital Lightning connector D．A, B and C