1.How long have you ________(be)collecting shells?
2.How long ________(did)you sleep last night?
3.When did you ________(start)class today.
4.When did you get your first pair of ________(skate)?
5.It's eight o'clock now. several ________(skate) are still skating.
6.I stayed in New York for two and a half ________(year).
7.Thanks for ________(ask)me to your party.
8.They are all ________(round)our apartment.
9.If you know anyone else who ________(collect)them, please let me know
10.I am ________(interesting)in the writer job.