Tâm mình rộng bao nhiêu?

Vớ vẩn. Tâm ý nghĩ đến vũ trụ thì tâm trí ta bao trùm vũ trụ. Tâm ý nghĩ đấn con vi trùng thì nó chỉ chứa được con vi trùng.

In our life there are two compounded mind formations: 

happiness and suffering

All compounded things prone to rise and fall; 

having risen, they're destroyed

their passing truest bliss.

A breath is a compounded thing

It prones to rise and fall;

having risen, they're destroyed

its passing truest bliss.

A breath is born and died

It passes away naturally,

without happiness or suffering

A natural mindfulness.

Think of this:

Why people don't use happiness and suffering but a breath for meditation practice?

Find it for yourself. 

A breath is born and passed away peacefully and mindfulness

Happiness and suffering should be born and passed away

in the same manners peacefully and mindfulness.

People are normally inhaling and exhaling naturally.