根据句意和汉语注释，在相应的横线上，写出单词的正确形式。
The hostess          （点头）to show that she agreed with us at the show.
I am often           (提供) some useful help by my teachers and classmates.
I have ordered several ________(册)of this book from abroad. Would you like to have one?
Can this kind of robot be           (可获得的) in the nearest supermarket?