Use of present simple in "I wonder what he does all day long?"

Question

Consider the sentence (which may in speech either be modulated to indicate an invitation to reply, signified here by the question mark, or not):

• "I wonder what he does all day long?"

The sentence sounds totally idiomatic. I don't really understand why the present simple is used here, if we use the present simple mainly for actions which are repeated after intervening periods of time (each month, week, year, etc). Can we also use it for situations etc lasting all day long ? We can imagine this as repeated actions occurring frequently all through yhe day?

Answer 1

"I wonder what he does all day long?" is not talking about a single day. It's implicitly talking about many days, in an ongoing fashion. You would use it about a person's job or regular activity, not about a particular day.

He is employed as a programmer but I've never seen him write code. I wonder what he does all day long?

If there were multiple days, but in the past, you would use the simple past:

He was employed as a programmer but I never saw him write code. I wonder what he did all day long?

If you were talking about a single day, or a few days, you would use the simple past or present continuous.

He went into the gardener's shed and didn't come out until evening. I wonder what he did all day long?

or

He was in the gardener's shed yesterday and again today. I wonder what he is doing all day long?