Choose the meter and line length of the line of poetry below. Time will not be ours forever

The correct answer should be trochaic tetrameter.

Tetrameter means that there are 8 syllables in one line - a meter consists of two syllables, and tetra means four, so if you multiply that, you get 8 syllables. On the other hand, a trochee means that a stressed syllable is followed by one unstressed syllable, which is the case in the excerpt above.