【单选题】在△ABC中,若b=12,A=30°,B=90°,则a=( )
【单选题】Our civilization can not be thought of as ____ in a short period of time.
【单选题】In such a short period of time, we can not think of our civilization as ____.
【单选题】在△ABC中,若 A=60°,BC=4 3 ,AC=4 2 ,则角B的大小为( )
【单选题】东北地区的( )始兴于本溪的九顶铁刹山。