Put in the infinitive or the -ing form of the verb in brackets

Put in the infinitive or the -ing form of the verb in brackets.
1. You should be able to practise _____________(sing) every day.
2. Scientists are hoping _____________(discover) a new chemical element.
3. I don't mind people _____________(ask) me questions.
4. He works too slowly _____________(be) any use to me.
5. He can 't stand _____________(wait) for other people.