An( )event in history took place in 1969 , when two American astronauts landed for the first time on the Moon.
A.insoluble B.unprecedented C.disappointed D.distrustful正确答案B
An( )event in history took place in 1969 , when two American astronauts landed for the first time on the Moon.
A.insoluble B.unprecedented C.disappointed D.distrustful正确答案B