I've managed to find the solution to the problem that's been bugging me all day.
You're the best thing that's ever happened to me.
- You are the best thing that has ever happened to me!
This is the best thing that's ever happened to me.
- This is the best thing that has ever happened to me.
That's the book I've been looking for.
... because it has a profound impact on ...
... who designs radio, radar, every engineer who deals with radar and radio has to memorize ...