What the difference between "he didn't be a doctor" and "he wasn't a doctor"?

  • 1
    Although 'He wanted to be a doctor' ('His desire was to become a doctor'), 'He intended to be a doctor', 'He was going to be a doctor' ... are all acceptable, 'He didn't be a doctor' isn't. 'He didn't become a doctor' does work. Commented Mar 13, 2017 at 16:35

2 Answers 2


In the grammatical sentence

  • He wasn't a doctor

the first auxiliary verb (was) is contracted with not to form wasn't.
That's the way the rule goes: Not may contract with the first auxiliary verb in a verb phrase.

In the ungrammatical sentence (the asterisk in front of it marks it as ungrammatical)

  • *He didn't be a doctor

The negative is not contracted with the first auxiliary verb, but rather be is treated as a main verb and Do-Support is invoked to insert the past tense of do as the first auxiliary verb, which is then contracted with not to produce didn't be. This is ungrammatical because be is always an auxiliary verb, and does not allow Do-Support (except in imperatives with Action do, like Do be quiet).

  • I suppose Be quiet, they shout. So they did be quiet is a kind of "mention" rather than "use". The main difference I see between that and ...they were quiet is that you could reasonably say that second version without particularly stressing were, but the first one only seems to work for me if did is heavily stressed. Commented Mar 13, 2017 at 19:22
  • Just a note to mention that, interestingly, BE might be considered a lexical verb in a few very specific environments, for example negative questions "Why don't you be more careful?" and conditional adjuncts "If you don't be more careful ..." In both of these types of clause we see DO support with BE. Commented Mar 14, 2017 at 16:39
  • Only optionally, however, and in -- as you say -- very specific environments. More normal would be If you aren't more carefu, ...l and Why aren't you more careful?. Both will be understood as inchoative (becoming more careful), and the version with do-support is marked as odd. Commented Mar 14, 2017 at 18:43

*"he didn't be a doctor"

is grammatically incorrect. I'm not sure what you're trying to express with this. Are you trying to say

"He didn't become a doctor"

Your other sentence,

"he wasn't a doctor"

is grammatically correct.

  • I think "He didn't become a doctor" more appropriate solution than "He didn't be a doctor". The second variant is grammatically incorrect. Please, edit my comment if I make grammatical mistakes. :)
    – angevad
    Commented Mar 14, 2017 at 9:31

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