用括号内所给词的适当形式填空。
1. I __________ never __________ ( see) such a wonderful film before.
2. How much money do we need to the job __________ ( proper)
3. I happened ___________ ( meet) my old friends in the street yesterday.
4. — ___________ he __________ ( be ) to Beijing before?
— Yes, he has.
5. __________ (thank) to your help, I can find my dog.