​One day a boy looked outside and saw a bank of grey clouds in the sky. The boy was called Jack. Jack wanted to be a weather scientist. A noise came from outside. It was thunder. His mum looked at the sky and said, “There might be a thunderstorm tonight!”Jack said, “There could be but, then again, it is probably just going to rain!”

Just then, on the other side of the world, a tornado was sucking up cars and destroying roads. Back in Australia, Jack was watching the news and it said that this storm was coming to Australia and everyone should stay indoors until tomorrow.

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Severe Weather

We can use have to + infinitive, must + infinitive, and should + infinitive to express obligation (something you have to do).

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Modal Verbs of Obligation