It was only with the help of special device ______ the information.

A．did they get

B．that they got

C．will they get

D．that they get

烟煤原煤灰分的符号是（），某工作面煤层灰分为18%，则属于（）煤，若灰分为10%，则属于（）煤，高灰煤的灰分含量范围为（）。