I'll go with you as soon as I ____ this letter.(will finish shall finish finish finished)

I'll go with you as soon as I ____ this letter.(will finish shall finish finish finished)
I'll go with you as soon as I ____ this letter.(will finish shall finish finish finished)

I'll go with you as soon as I ____ this letter.(will finish shall finish finish finished)
I'll go with you as soon as I finish this letter.
我一写完这封信就和你一起去.

finish

finished

finish