Tenses and Sentence Rephrasing Quiz

Over the past decade, the government (a)   (introduce) several laws to reduce air pollution.

Environmentalists (a)   (campaign) for cleaner oceans since the 1990s.

The global temperature (a)   (rise) steadily due to climate change.

Scientists (a)   (study) the effects of deforestation for many years.

Many species (a)   (become) endangered because of habitat destruction.

By the time the rainforests were destroyed, thousands of species (a)   (already/disappear).

Before the city enacted recycling policies, people (a)   (not/bother) to sort their waste.

When the fire broke out in the forest, firefighters (a)   (try) to control the situation for hours.

They (a)   (not/realize) the harmful effects of plastic waste until it was too late.

Before the cleanup operation started, volunteers (a)   (collect) rubbish for several hours.