Grammar didactic layout, characterized because it is constituted by a cover composed of two juxtaposed rectangular sheets, joined together by longitudinal strips that determine between them free spaces, of regular width and open at both ends, having within each space a sliding strip along them by manual operation by means of a central handle that protrudes through an axial groove of each space in the front face of the sleeve, whose strips contain in column a series of corresponding expressions in each strip to a part of the sentence, all this in such a way that in each case conveniently moving said strips, it is possible to compose complete grammatical sentences legible by a front box of each space, all of them being located at the same level, and the corresponding sheet being transparent. (Machine-translation by Google Translate, not legally binding)
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