Englishfor English speakers
two
Determiner
—
The number 2. Two means more than one and less than three.
We have two eyes and two ears.
two
Noun
—
The number 2.
One and one is two.
factor
Noun
—
A factor is one of a number of things that causes a result.
The main factor in the success of our program is our excellent teachers.
theory
Noun
—
A theory is an idea that tries to explain an observation.
The new information showed that his theory about growth was incorrect.
Nobody has disproved Einstein's theory of general relativity.