Answer:
I know a word of letters three. Add two, and fewer there will be!
It stands upright and can be quite grand. Its secret is not hidden but right at hand. What is it?
What can run but can’t walk?
Being able to interpret the letters on this screen proves that you have this quality.
What's as small as a mouse but guards a house like a lion?
When is it bad luck to see a black cat?