how do I write this clause in the past

Clear, not clearly.

I had to be more clear is grammatically okay, but I think you might mean "I should have been more clear," if you are comparing how clear you actually were with how clear you needed to be (to make your meaning known).

Ugh. That was a terrible explanation. But does it make sense anyway?

Nader75how do I write this clause in the past

I have to be more clearly .

I wote it like this : I had to be more clearly .

"Clearly" is an adverb, not an adjective. "To be more" must be followed by adjective. Adverb modifies verb or another adverb but can not be used alone in a sentence.

e.g. "John was

you mean I must to said :

I had to be more definitely clearly ... is thsi true

No Nader. Please read my post.

I had to be more clear.

I should have been more clear.

I had to be more clear than I had been in the past.

Nader75you mean I must to said :

I had to be more definitely clearly ... is thsi true

Nader,

Grammatically, adverb-adverb is the wrong sentence construction without an adjective which is what you have in the above. With the wording your have, You may say " I had to be definitely