Los estados de la materia — Los gases

Segunda edición, revisada, de este texto pedagógico, claro y coherente, concebido como un medio para aprender español como lengua extranjera pero cuyas propuestas descriptivas inéditas de la gramática le hacen también interesante al nativo. Su objetivo es acelerar al máximo el proceso de aprendizaje. Obra original que se echaba en falta para poder llevar a cabo una buena labor docente.

During the American Civil War, the United States was on the brink of falling apart irrevocably. As states seceded and brother turned against brother, hope for reconciliation was dim. This conflict, an essential topic of the social studies curriculum, is skillfully presented from its origins in the Southern slave-trade economy to bloody battles and, later, Reconstruction. Striking photographs and artwork of integral events and people will resonate with readers, while interesting sidebar information gives them more to reflect on about this terrible war and the lessons it taught us.

There are many steps in the nitrogen cycle that include difficult concepts and words: denitrification, prokaryotes, ammonia, and more. With the help of this understandable book, even struggling readers will grasp this cycle of nature. Low-level language, fact boxes, and an extended glossary provide readers with essential vocabulary explanations that allow them to further understand each step of the cycle. Full-color diagrams aid readers' comprehension as they move through the cycle from start to finish, and then around again.

Material didáctico, sencillo y práctico, estructurado en ocho ejes temáticos que recogen todos los elementos del sonido.