'close them off' is a correct phrase in written English.
You can use it when describing a situation where you are preventing something or someone from having access to something. For example, "We had to close them off from the rest of the building while they performed the maintenance work".
You can close them off when they're not needed -- the two simple louvers fold flush into their housing.
In a surprising decision last year, Mr. Shumway decided to return all outside money in his funds and close them off to new external investments.
But how do schools tell children about religion in a way that is fair, objective, unbiased and, most important, doesn't close them off to alternatives?
In this light his collecting was another way of being porous to the world, and his being porous another way to defend against images and objects - that is, to drain them of affect, to close them off again.
Birch plywood sliding doors close them off for sleeping or open them to the courtyard's glass walls; other sliding doors, between rooms, allow suitelike spaces for parents with children.
Both the office and the kitchen are enclosed by translucent panels, which hide any mess but light the spaces and don't close them off as conventional Sheetrock walls would.
By far the most distinguishing characteristic of the Roman theatres, however, was the redesigned scene building that closed them off from the outside world.
Outside my house or at school, the few people I recognize all have headphones on, like a giant billboard with a "DO NOT DISTURB" poster closing them off to any human interaction.
We've figured out things that people might try do to us and closed them off," said Kenneth M. Pollack, deputy director of national security studies at the Council on Foreign Relations and a former official at the Central Intelligence Agency.
Yet his heart liesvery much, one feels, in opening up possibilitiesrather than in closing them off, andin what he calls "allegory and obscurity .In some ways, all his books are about hissense that two souls are better than one.As he told The Paris Review in the contextof cultural eclecticism: "Schizophreniamakes you intelligent".
Wagner's texts for the four operas in his Ring cycle mimicked the alliteration of ancient Nordic verse: he believed that those recurring sounds at the beginning of words kick-started his lines rather than closing them off in predictable endings as rhyme does.
