1. (leave) the key in my office,I had to go back and get it.
答案:Having left
2. (not receive) a reply from his Australian friend,Herbert decided to write an e-mail to him again.
答案:Not having received
3.He worked for an hour and then he stopped (take) a rest.
答案:to take
4.I regret (say) that I can’t attend your 18-year-old birthday party.
答案:to say
5.I’ll never forget (see) my daughter dance in public for the first time.
答案:seeing
