I just came over to find out how the mistake had occurred.

At the same time it was difficult to see how a mistake could have occurred.

The mistake occurred in March 1988, when a water line was being installed to a new building.

The president was shocked that such a mistake could occur.

Such mistakes occurred frequently enough for my parents to suspect nothing.

On the first night a mistake occurred which might have proved fatal.

My heart turned to water, for there was no sign of the stone, and I knew that some terrible mistake had occurred.

One such mistake, she said, occurred in her direct testimony yesterday.

Ms. Patterson said she did not know how the mistake occurred.

Problem of the second random process is that genetic mistakes can occur.