have vs had (Things have changed because something happened to him exactly...)

[tweak]

dear teachers,

Things have changed because something happened to him exactly two years ago.

why use have instead of had? isn't the sentence a past tense?

thanks!

tweak

[Mister Micawber]

.
Yes, but both 'have' and 'had' work in the past. 'Have' because the speaker refers from a past point up to now.
.
_________________
Canadian-American native speaker
who teaches English for a living at Mister Micawber's
ESL cafe: Interview with Mr. Micawber