past simple & past continius

past simple:

Is used for speak to accions to happened in a moment and is specific for expressions to last time...(yesterday, the day before yesterday, last night, last week, last year...)

When I was young I lived in Madrid

past continius:

it's forms with the past of the verb sees + the gerund of the verb that is wanted to conjugate.

and it's used for:

• In order to express an action that was being developed in the past but and we do not have information of its end [It was raining]
• In order to express two actions that are developed simultaneously [I was reading the newspaper while I was walking home ]
• In order to express two actions that are developed in the past, one of which had its beginning before the other [When I arrived John was talking on the phone]

credits:

english.baladre.org/sedaviwebfront/pastsimplecontinuous.htm

www.lamansiondelingles.com

problems our planet

geenhouse effect- the earth is heats because the small part of solar energy is absorbed and other is returned to sapce and the last part arrived to earth and heats to the superficie.

ozone layer- the ozone layer protec the word for the ultra violet rai. the layer is affected
Chlorofluorocarbons and for the polucion.

radiation nuclear- nuclear plant produce small pieces of waste. But the principal danger is nuclera accident chernobyl .

credits: wikipedia, wikipedia (greenhouse effect)