Mistakes and students go together. Otherwise, pupils would be teachers. English – a language of few infallible rules – is fertile land for blunders and I have been listening to and committing them for years. One day I started to keep a list of the most common slips and ended up with around three hundred. After eliminating the least frequent I listed the remainder, which you’ll find below. Even though I have strived to include the most common errors this list is – as many others – arbitrary. I therefore apologise to those faults who feel their prevalence makes them belong here and to those who are in but consider themselves exceptional and would.