GOD'S WORD® Translation
He found them asleep because they couldn't keep their eyes open. They didn't even know what they should say to him.

American Standard Version
And again he came, and found them sleeping, for their eyes were very heavy; and they knew not what to answer him.

Berean Study Bible
And again Jesus returned and found them sleeping—for their eyes were heavy. And they did not know what to answer Him.

Douay-Rheims Bible
And when he returned, he found them again asleep, (for their eyes were heavy,) and they knew not what to answer him.

English Revised Version
And again he came, and found them sleeping, for their eyes were very heavy; and they wist not what to answer him.

King James Bible
And when he returned, he found them asleep again, (for their eyes were heavy,) neither wist they what to answer him.

World English Bible
Again he returned, and found them sleeping, for their eyes were very heavy, and they didn't know what to answer him.

Young's Literal Translation
and having returned, he found them again sleeping, for their eyes were heavy, and they had not known what they might answer him.

Mark 14:40 Additional Translations ...