Flip tax filing question - this year or next year ?

[Pandu Chimata]

We bought a property for flip last year and we have completed all the work last year but the house is still on sale. All construction expenses are incurred last year only but the house is still on sale. 

Should I be filing all my construction expenses this year or should I wait till the house sold out to file the expenses which means next year ?

Please advise.