Please hold the banister firmly when you go up the stairs.

He used a file to smooth the wood.

I saw an eastern buzzard in the park.

He firmly gripped the banister when climbing the stairs.

He always grabs the banister when he goes up the stairs.

He was using a file to make a key.

He started the printing of the new book.

This paper is very thin.

I make origami using paper.

Do you understand the necessity of this project?