信托
参考答案：
接受他人信任与委托，代为经营财物或代办事务，为指定的人谋取利益的经济行为。
____ abroad for two years, the two astronauts went back home last year.
A．Educating
B．Educated
C．Having been educated
D．being educated
电流是如何形成的？
