Choose the best answer to complete the passage.

Last Sunday Nam and many of his friends (16) ___________ a book fair in his neighbourhood. The book fair is an annual charitable activity with a view to collecting money and used books, and donating them (17) ___________ poor students in his community. Like other friends, Nam donated some used student’s books and bought some English short stories, comics and Vietnamese novels. He hoped he could make a small contribution to his community by doing so. There (18) ___________ also some interesting competitions in the book fair, such as answering quizzes about famous books, composing poems, solving secret coded messages, etc. The (19) ___________ received various gifts like handmade cards, cute teddy bears or school things. Unluckily, Nam didn’t win any games, (20) ___________ he still felt very happy.