1 He had better turn/turning himself in. 2 I'm sorry to hear/hear that you're ill. 3 What's the use of lock/locking the front door if you leave the windows open? 4 I don't want to risk speeding/to speed - it's against the law! 5 Jenny called the police to assist/ assisting her 6 You mustn't to download/download music without paying for it.
