Supply the correct verb form

Supply the correct verb form: Present Tenses
1) Up to the present , we (write) almost every lesson in the book 
2) The earth ( circle) the sun once every 365 days
3) The farmers ( work) in the field at the moment 
4)  How many times you ( see) him since he went to Edunburght
5) Rivers usuall ( flow) to the sea