tore, tour

Tore or tore is the past tense ( yesterday, or some time ago ) of tear, meaning to rip or rend--
He tore his shirt, and went home to change.
We tore up bits of paper to make confetti.

Tour or tour ( rhymes with tore ) means a visit to examine or have a look at some new place--
They took a tour of Paris while on vacation.
They went on a guided tour of the museum.
Tour may also be used as a verb ( action word )--
We will tour the islands next spring.
We like to tour new places.

Now that you know that, you can say--
"He tore his shirt while on a tour of the new factory."

Note--"tor" ( rhymes with tore ) means a rocky pinnacle or mountain peak--
He took several photographs of the tor with the sun setting behind it.
Note # 2--"torn" is a modifying ( describing something ) form of "tore"--
His shirt is torn.
He tore his shirt.
"Torn" is also a participle ( used with a helper verb ) to show that the action is over or complete--
He went home after he had torn all of the papers to bits.
The dog has torn up all of the grass.
Your shirt is torn.