根据对话内容，从方框内选出能填入空白处的最佳选项，其中有两项为多余选项。

A: Look at that strange thing, Wei Hua! What’s that?
B: It’s a key.             
A: Our autobike (电动自行车)?   
B: It was invented by my father. It’s a battery-operated（电池驱动的）machine.
A:    
B: It’s used for riding or flying.
A: Flying? ______
B: You can just ride it like a autobike and it will fly as it goes faster enough.
A: ______ I think your father is so great!
B: I think so. He has invented many things.