en_tn/rev/08/08.md

The second angel

"The next angel" or "Angel number two" (See: rc://en/ta/man/translate/translate-ordinal)

something like a great mountain burning with fire was thrown

This can be stated in active form. Alternate translation: "the angel threw something like a great mountain burning with fire" (See: rc://en/ta/man/translate/figs-activepassive)

A third

"A third" is a fraction. (See: rc://en/ta/man/translate/translate-fraction)

became blood

Possible meanings are it 1) "became red like blood" or it 2) really became blood. (See: rc://en/ta/man/translate/figs-simile)