The document provides instructions to fill in the blanks of 10 sentences with the appropriate verb tenses, including the Simple Past, Past Perfect, Present Perfect, Present Perfect Continuous and Gerund tenses. The sentences cover various topics around recycling, environmentalism and global warming such as visiting a grandmother to teach her about recycling, working for an environmental organization, watching a documentary, and efforts to control carbon dioxide emissions.

1. VERB TENSES REVISION
Fill in the gaps with the verbs in the Simple Past, Past Perfect, Present
Perfect, Present Perfect Continuous and the Gerund
1. Last week I ____________(visit) my grandmother and I ________ (teach) her how
to recycle packaging.
2. Lionel ___________(work) for this environmental organization since 1983. Now he
is the director.
3. We _________ (already/watch) An Inconvenient Truth, by Al Gore. We liked it a
lot.
4. Yesterday I _______ (buy) some energy-saving light bulbs to replace the ones I
have now.
5. My parents believe that it is a waste of time ____________(separate) the rubbish.
6. I __________ (recycle) packaging and glass ever since I was a child.
7. It’s worth __________ (try) to fight against all types of air pollution.
8. Al Gore __________ (do) lots of research before he started presenting the facts
on global warming.
9. In China there’s great difficulty in __________ (control) the carbon dioxide
emissions caused by cars.
10. It’s a fact that there are a lot of things that I ________ (do) wrong so far and I
_____________ (never/think) that I could do something for our planet.