阅读下面短文,在空白处填入1个适当的单词或括号内单词的正确形式。
While they are at home alone, many people imagine (have) the opportunity (sing) together, which (realize) by a virtual choir. Anyone can take part in from anywhere and does not need a studio. It (prove) to be a positive influence on the lives of many people. Award-winning composer and conductor Eric Whitacre came up the idea of the virtual choir, began studying music in 1988. (finish) university in 1995, he received a master's degree in (music)composition in 1997. In 2009, his first virtual choir received, (million) of views on the Internet. The virtual choir has become a worldwide phenomenon since then. In 2014, he formed the Virtual Youth Choir for UNICEF, and 2, 292 young people from 80 countries sang his song"What If".