Is 'is' oblgatory?

Re: Is 'is' oblgatory?


Quite the contrary, his English was obstreperous.

I do not think his English is very good.

I did not think his English was very good.

Many thanks for your replies.

You don't need the"is", but both of Tico's examples are correct uses of it.

You can also say "I do not think his English was very good" if you referring at the present to a thought you had in the past - reporting on an earlier interview with a job applicant, for example.