用括号内所给单词的适当形式填空，每空格限填一词。
We can see many____________ (potato) in the supermarket.
My grandparents live on the ____________  (nine) floor of a tall building.
If at first you don’t ____________ (success), try, try again.
____________ (lucky), Fred was not hurt in the car accident.
They have invited a____________ (science) to give them a speech on space.
Eating vegetables every day makes us ____________  (healthy) than before.