Ответ:

➀ If global warming doesn't stop soon, the ice caps will melt.

→ The ice caps will melt unless global warming stops soon.

➁ I don't have a bike so I can't cycle to work.

→ If I had a bike, I would cycle to work.

➂ I advise you to take the bus.

→ If I were you, I would take the bus.

→ If I were in your shoes, I would take the bus.

➃ Water becomes ice when it freezes.

→ If water freezes, it becomes ice.

➄ I'll take the rubbish out unless it's raining.

If it is not raining, I'll take the rubbish out.

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