Spelling can be a tricky business. But it's not just child's play - adults have problems too.
BBC One's Hard Spell, in which children compete to see whose spelling is best, may have reminded many people of their school days.
But spelling is not just child's play, and even for the best of adult spellers, there are sometimes words which just escape their radar.
Author Vivian Cook, whose book, Accomodating Brocolli in the Cemetary, looks at many common mistakes in spelling, points out that six out of 10 15-year-olds cannot write 10 lines without making an error, while there are words which adults struggle with all their lives.
So here, as guest question-master, Cook has chosen 10 of his favourite mistakes. In each question, only one option is correct.