Directions: Read the passage carefully and answer the questions or complete the statements in no more than 12 words．
The iPad is a tablet computer designed and developed by Apple．It is particularly marketed as a platform for audio and visual media such as books, periodicals, movies, music, and games, as well as web content．At about 700 grams （25 ounces）, its size and weight are between those of most contemporary smart phones and laptop computers．Apple released the iPad in April 2010, and sold 3 million of the devices in 80 days．
The iPad runs the same operating system as the earlier iPod Touch and iPhone．It can run its own applications as well as ones developed for the iPhone．Without modification, it will only run programs approved by Apple and distributed via its online store．
Like iPhone and iPod Touch, the iPad is controlled by a multi-touch display ?a break from most previous tablet computers, which used a pressure-triggered stylus（尖笔）．The iPad uses a Wi-Fi data connection to browse the Internet, load and stream media, and install software．Some models also have a 3G wireless data connection, The device is managed and synced（同步） by iTunes on a personal computer via USB cable．
Media reaction to the device has generally been neutral or positive, with more positive reaction after the device was launched．
（Note: Answer the questions or complete the statements in NO MORE THAN 12 WORDS．）
1．The Marketing Strategy of iPad is to make it ____ for audio and visual media．
2．The programs approved by Apple can only be bought from ____．
3．How do people control some previous tablet computers?
4．What's the media reaction to the device prior to its launch?