Normally, these valves open to let blood flow through or out of your heart, and then shut to keep it from flowing backward.

In particular, pilings may not have been driven deep enough to keep water from flowing underneath.

We've got valves in our veins, to keep blood from flowing backwards.

The inflammation narrows the arteries, which keeps blood from flowing well.

By propping up outmoded producers, they are keeping resources from flowing to products the country needs and the world wants.

A special mesh keeps the bacteria from flowing out of the individual pools.

A citywide drought emergency kept the fountain - like most across the city - from flowing with water.

After all, even their ancestors' early efforts to dynamite the aqueduct could not keep the water from flowing away to serve a city of millions.

He couldn't keep the tears from flowing when the boy was no longer strong enough to stand.

When you do, you still have to hold on to keep from flowing back down.