单句语法填空
1．(2017·天津卷)Nowadays, cycling, along with jogging and swimming, ___________ (regard)as one of the best allround forms of exercise.
答案：is regarded
2．(2016·浙江卷6月)While online shopping ___________ (change) our life, not all of its effects have been positive.
答案：has changed
3．(2018·长春外国语期中)Christmas is the most important festival in the western world. It ___________ (fall) on December 25.
答案：falls
4．Look! The twins ___________ (help) their mother do the housework while other children are playing games.
