题干
He sometimes goes out to ________ with my friends at weekends.
A：play
B：plays
C：playing
D：played
答案(点此获取答案解析）
A
2SO3(g)，能增大正反应速率的措施是（ ）
郊区)双向车道车速变化曲线图”，完成下面小题。