请根据要求改写下列句子,每空一词。
Her father has been on the phone since half an hour ago. (对划线部分提问)
_________ _________ has her father been on the phone?
I think diving is the most difficult activity of all. (保持句意基本不变)
I think diving is more difficult than __________ __________ activity.
We can put those machines on the ground floor of the building. (改为被动语态)
Those machines can __________ __________on the ground floor of the building.
The beach is a nice place for tourists. (改为感叹句)
___________ __________ nice place for tourists the beach is!
Pingping is so energetic that he can be a good monitor. (改为简单句)
Pingping is ___________ ___________ to be a good monitor.