【B17】A．transactionB．transitionC．transmissionD．tra

【B17】A．ordersB．messagesC．wordsD．letters

【C17】A．transactionB．transitionC．transmissionD．transformation

The BBC has just successfully demonstrated a new digital radio______system.A．transactionB．

【B17】A．commonB．unknownC．modernD．famous

【B17】A．actB．voiceC．behaveD．do

【B17】A．beforeB．previousC．agoD．former