We were busy ________ (get) things ready for the trial production when he phoned us.
getting
暂无解析
Wooddoesnotconductelectricity;________.
Thistest________anumberofmultiplechoicequestions.
heteachertoldthemsincelight________(travel)fasterthansound,lightning________(appear)togobeforethunder.
I know it isn ’t important but I can ’t help ________ about it.