根据下列各句句意和空白之后的汉语提示词，在答题卡指定区域的横线上写出对应单词的正确、完整形式，每空只写一词。
(1)Both English and French are o__________ languages of Canada.
(2)Our school is a non-smoking one. So smoking is b_________ in our school.
(3)Water is the c__________ of oxygen and hydrogen.
(4)The organization needs more v__________ to do the work for free.
(5)My key is n__________ to be found. I don’t know where on earth I have left it.