'Single' in the Bible

Yet Elijah wasn't sent to a single one of those widows except to one at Zarephath in Sidon.

The light of the body is the eye: therefore when thine eye is single, thy whole body also is full of light; but when thine eye is evil, thy body also is full of darkness.

And which of you by worrying can add a single hour to his life’s span?

Every single one of them began asking to be excused. The first told him, "I bought a field, and I need to go out and inspect it. Please excuse me.'

Then, turning to His disciples, He said, "There will come a time when you will wish you could see a single one of the days of the Son of Man, but will not see one.

From that time, however, no one ventured to challenge Him with a single question.

Jesus said, “I say to you, Peter, before the rooster crows today, you will [utterly] deny three times that you know Me.”