Her presence had prevented him from giving chase to the gunman.

The presence of an international team can sometimes prevent attacks on refugees.

And the presence of foreign troops would prevent us from taking the necessary steps against terrorists.

But the presence of this woman did not prevent Milady from thinking.

The presence of may prevent us from drawing such a conclusion.

The presence of six minor candidates prevented either candidate from getting the necessary 50 percent majority.

In many cases, the presence of water can prevent a reaction from happening, or form undesirable products.

Luminol's presence may prevent other tests from being performed on a piece of evidence.

But the presence of the US military did not prevent the four tourists from being killed.

Her presence could prevent something from happening, or give us a better chance of finding how it happened.