A:①
B:①②
C:①②③
D:①②③④
We enjoy studying here very much, because the classroom by the cleaner every day.
20世纪60年代末,日本确立了“科技立国”政策,经济开始跃居世界第二,并开始谋求政治大国的地位。( )
A是____,B是____,C是____,D是____.