Astronaut Force Base. Astronauts is training must learn how to control and fly the Space Shuttle and, it is vital that they are familiar with the International Space Station so they know what they must do when they get there. Mission Specialist Educators, or "Educator Astronauts", were first selected in 2004, and as of 2007, there are three NASA Educator astronauts: Joseph M. Acaba, Richard R. Arnold, and Dorothy Metcalf-Lindenburger. Barbara Morgan, selected as back-up teacher to Christa McAuliffe in 1985, is considered to be the first Educator astronaut by the media, but she trained as a mission specialist. The Educator
Chinese as a foreign language Chinese language proficiency exam program, which tests has been taken around 100 million times (including by domestic ethnic minority candidates). Within China's Guangdong Province, Cantonese is also offered in some schools as optional or extra-curricular courses in select Chinese as a foreign language programs, although many require students to be proficient in the Mandarin first. Chinese is rated as one of the most difficult languages to learn for people whose native language is English, together with Arabic, Japanese and Korean. According to the Foreign Service Institute, a native English speaker needs over 2,200 hours of intensive study, taking 88 weeks