Imperial units commonly used units for length are (li), (tseung/cheung), (tsek/chek), (tsun/chun), (fen/fan) in descending scale order. These units are now rarely used in daily life, the imperial and metric systems being preferred. The imperial equivalents are written with the same basic Chinese characters as the Chinese system. In order to distinguish between the units of the two systems, the units can be prefixed with "Ying" () for the Imperial system and "Wa" () for the Chinese system. In writing, derived characters are often used, with an additional (mouth) radical to the left of the original Chinese character, for writing imperial units.
Imperial Gift Army). The Imperial Gift enabled the formation of the Royal Australian Air Force on 31 March 1921. An Air Board, answering to the Minister for Defence, would administer the new service. Imperial Gift aircraft were shipped to Australia in 1919, assembled upon delivery in 1920 and served for up to 10 years. The Airco/de Haviland DH-9a (A1-17/F2779) was the longest serving Imperial Gift aircraft, being written off on 4 February 1930. The only original surviving Imperial Gift aircraft in Australia are an Avro 504K (A3-4/H2174), stored at the Treloar Technology Centre (Canberra) and an S.E.5a (A2-4/C1916), in the collection of