People _____ ______(build) eco-friendly houses to reduce pollution.
People have built eco-friendly houses to reduce pollution.
The government _____ ______(create) new laws to protect forests.
The government has created new laws to protect forests.
Scientists _____ _______ (study) the effects of climate change for many years.
Scientists have studied the effects of climate change for many years.
Our community _____ ______ (plant) trees to improve the air quality.
Our community has planted trees to improve the air quality.
She ____ _______ (write) an article about renewable energy.
She has written an article about renewable energy.
