The given couplet is from Andrew Marvell's poem To His Coy Mistress.
We need to identify the syllabic type of the couplet.
Let us count the syllables in the first line:
\[
\text{The grave's a fine and private place}
\]
The line has approximately eight syllables.
The second line:
\[
\text{But none, I think, do there embrace}
\]
also has approximately eight syllables.
A line of eight syllables is called:
\[
\text{octasyllabic}.
\]
Therefore, the couplet is an octasyllabic couplet.