Bon's tips EFL grammar exercises

Examen de Selectividad (9)
(Lee las instructiones para el examen)

Un ejercicio para 2º Bachillerato
(An exercise for Advanced students.)

Lee el texto y contesta las preguntas. Cuidado con la puntuación y las mayúsculas.
(Read the text and answer the questions. Pay attention to punctuation and capital letters.)


For hundreds of thousands of years, the human race has thrived in Earth's environment. By 1800 there were 1 billion people on the planet. That number had doubled by 1975. If current birth rates hold, the present population of 5.1 billion will double again in 40 years. The frightening irony is that our success as an organism could condemn the Earth as a human habitat. We have upset nature's sensitive equilibrium disgorging noxious gases into the atmosphere, dumping toxic waste into rivers and oceans and tearing up the countryside to accommodate our rubbish.
What would happen if we did nothing about the threat to the Earth? Computers project that an accumulation of carbon dioxide in the atmosphere could drive up the Earth's average temperature from 3ºF to 9ºF by the middle of the next century. Sea levels would rise by several feet, flooding coastal areas and ruining vast tracts of farmland. Huge areas would be infertile and become uninhabitable. Water contamination could lead to shortages of safe drinking water.
In the last decade of the 20th century, we are at a crucial turning point. The actions of those now living will determine the future and possibly the very survival of the species. Spurred by poverty, population growth, ill advised policies and simple greed, humanity is at war with the plants, animals and elements that make up the planet and provide for our continued existence.
We only have a few years to attempt to turn things around. We must review our wasteful, careless ways; we must recycle more, conserve energy and adapt our lifestyles for the sake of those who will inherit the planet.