强调句练习题It was not until 1920 _ regular radio broadcasts began.A. which B. when C. that D. since2. It _ Mike and Mary who helped the old man several days ago.A. was B. are C. were D. had been3. She said she would go and she _ go.A. didnt B. did C. really D. would4. It was the training _ he had as a young man _ made him such a good engineer.A. what; that B. that; what C. that; which D. which; that5. Were all three people in the car injured
