Japan has been trying to bring its nuclear crisis under ____ control, but ____ spread of radiation has raised concerns about the safety of the nuclear energy.

A．a; the

B．the; /

C．/; the

D．a; /

如图所示的三个人造地球卫星，则说法正确的是（   ）

①卫星可能的轨道为a、b、c  ②卫星可能的轨道为a、c

③同步卫星可能的轨道为a、c  ④同步卫星可能的轨道为a

A．①③是对的

B．②④是对的

C．②③是对的

D．①④是对的