10.28 'what' or 'all' to focus on an action

If you want to focus on an action performed by someone, you can use a cleft sentence consisting of 'what' followed by the subject, the verb 'do', the verb 'be', and an infinitive clause with or without 'to'.

For example, instead of saying 'I wrote to George immediately', you can say 'What I did was to write to George immediately'.

• What Stephen did was to interview a lot of old people.
• What you have to do is to choose five companies to invest in.
• What it does is draw out all the vitamins from the body.
• What he did was get Christopher followed by a private detective.

You can use 'all' instead of 'what' if you want to emphasize that just one thing is done and nothing else.

• All he did was shake hands and wish me good luck.
• All she ever does is make jam.