单项选择题
John worked late into the night， （）a speech for tomorrow’s meeting.
A.preparing B.to prepare C.was preparing D.prepared
单项选择题 Respectforthelawisthefoundationofcivilizedliving，（）breaksitwillbepunished.
单项选择题 Hismarkedchangesinpersonalitywere（）byaseriesofunfortunateeventsinhislife.
单项选择题 Mostofthestudentsaresaidto（）theproposednewtrainingsystem.
