Cambridge Grammar of English Hardback with cd-rom a comprehensive Guide

Temporal subordinators and the present perfect

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Temporal subordinators such as after, as soon as, before, once, until, when can

refer to finished events at points and periods of time in the future as seen from the

present moment. In such cases they occur with the present perfect simple:

Tell me 

after

I

’ve eaten my dinner, because I want to enjoy it.

I’m going to start revising 

as soon as

I

’ve done this project.

Once

I

’ve become more familiar with the territory, maybe I’ll be able to find

things for myself.

Shall I give you a ring 

when

I

’ve sorted the invoice out?

(Shall I give you a ring when I will have sorted the invoice out?)

The same subordinators may also refer to past events completed at the moment of

speaking, or to past events still relevant at the time of speaking/writing, especially

when such events are seen as generally true. Such references also occur with the

present perfect simple:

Once

you

’ve bought a house, you start falling into trap after trap, you know,

mortgage and bills, and buying things for the house, and things that’ll make it

comfortable, and what have you.

You’re put into a medical ward 

after

you

’ve been treated in the coronary care

unit.

When

I

’ve been out to buy something and I see the price, it shocks me that

things are so expensive.