Do or Does for emphasis

I thought you could use “do” for emphasis as in:

This does bear thinking about. (emphasis)
They do seem very happy.

Or is the negative always used before a verb in the present tense? (S) do (not) verb

This doesn’t bear thinking about.
They don’t seem very happy.

Can you not use do before a verb in the present tense for emphasis?

Thanks in advance for all your support and guidance. I am in your debt. Belles

Hi Belles,

You can indeed use ‘do’ as you have suggested for the present positive use. The use of ‘do’ with a present negative is required with verbs (with the exception of ‘be’ of course).

Your third question: Can you not use do before a verb in the present tense for emphasis? I assume means are there other ways to express emphasis? The only way you can do this is by adding adverbs that indicate that you want to stress something as in:

This really bears thinking about.
They certainly seem happy.

Alan