单项选择题
Having been told that her son died in the accident, the old woman appeared very calm, as if nothing （）.
A. happened B. were happened C. was happened D. had happened
单项选择题 Having been praised by the teacher, the little girl ran back home, （）.
单项选择题 By the end of last week. 611 people from 49 countries （） to attend the meeting, with nearly half coming from the United States, Germany and Britain.
单项选择题 Skating can be good for you （） correctly.
