从方框中选词并用其适当形式填空

describe; nobody; potato; reason; terrible

①What's your ____ for asking for so much money, dear?

② We know you had an unusual experience, but could you please ____ it more carefully?

③ —How's the food there in Europe during your vacation?

—It's really ____! They eat many things without cooking!

④ —Who helped you work out the problem?

—____! I made it myself after ten minutes' hard work.

⑤ —Do you like eating vegetables?

—Yes. I like ____ and tomatoes best.

已知点B在直线AC上，线段AB=8cm，AC=18cm，P、Q分别是线段AB、AC的中点，则线段PQ=____

请回答：