1.He had to stay at home to look after his mother yesterday.
2.It usually takes me half an hour to finish my homework.
3.listen!There is someone singing in the next door.
4.You will find the post-office at the end of the street.
5.I think dive is the most difficult sports event.
6.To keep fit,you should take exercise for 15 minutes every day.
7.How long did Jim stay in Hangzhou last month?