High clouds kept blocking out the sun, sending long, gray shadows over the back lawn.

But low clouds, rain or fog will keep you on the ground.

The cloud kept going, its underside already becoming once again a nice, even, fluffy white.

The moon sailed into the sky, but clouds kept hiding her light.

That cloud must be heavy and keep the molecules of the decaying body from going far.

I feared the clouds would keep me from fully contacting my master.

The huge cloud of purple blackness kept on boiling higher into the sky.

There was a half-moon above, but clouds kept drifting across it.

"I fear so; the cloud keeps at a great height."

A cloud doesn't keep its shape and/or its size forever.