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

THE PRESENT PERFECT

351

Time up to now 

351a

The present perfect (simple and progressive) is used to refer to events taking place

in a past time-frame that connects with the present:

events

past

now

So, what

’s been happening since the last time we met? 

(from that moment till now)

In fact, alligators 

have killed only eight people in Florida in the last half-century. 

(in the fifty years up to the time of writing)

The present perfect progressive can place greater emphasis on the duration of an

event up to the present moment and can indicate an uninterrupted action:

I

’ve been waiting for you for over an hour.

know

like

mean

smell

taste

think

understand

want