There's a time at which everyone eats every doughnut
Dictionary
E3
P1
D1
T1
The predicate "E3" stands for " _ eats _ at _ ". We start by converting the sentence into the form that fits this predicate: "everyone eats every doughnut at some time." From this we arrive the hybrid matrix above.

All dogs bark
Someone works for Nadia
Everyone loves someone
Some cup was put on every table by some man
Only philosophers wear only diamonds
Every cat that cleans himself cleans an animal that catches mice
If someone is tall, then he is bigger than Rachel
Every dog that has an owner obeys him
The man Karen adores is friends with Bob