Front

Use 'ought to' and 'should' for advice.

Back

True

Front

Using can indicates a choice.

Back

True

Front

You need a ticket before boarding the train to pass the checkpoint.

Back

have to buy

Front

We use 'mustn’t' or 'can't' to indicate something is not allowed. 'Mustn’t' is for rules we make, while 'can’t' refers to others' rules. We still.............cross the street, the traffic light is still red.

Back

can't

Front

No obligation: I ............... call a taxi. Roberto took me home after the game.

Back

didn’t have to