1 a Read the text, then look at the highlighted -ing and infinitive forms. Which form do we use: after modal verbs, after adjectives, to show purpose, after certain verbs (decide, appear), after prepositions, as a noun, after expressions (I'm busy etc), after certain verbs (fancy, start, avoid, spend, imagine, suggest etc)? Check in the Grammar Reference.

This section provides rules about when to use the infinitive or -ing form of a verb. It explains that the infinitive form is used after modal verbs, after adjectives to show purpose, and after certain verbs like 'decide' and 'appear'. The -ing form is used after prepositions, as a noun, after expressions like 'I'm busy', and after certain verbs like 'fancy', 'start', 'avoid', 'spend', 'imagine', and 'suggest'. You should consult the Grammar Reference for more detailed explanations and examples.