Question

we (do ) it had we know about it (write in correct form of tense)​

Answer 1

Answer:

we done it had we know about it( do-done)

Answer 2

we (do ) it had we know about it (write in the correct form of tense)

Answer:

We would have done it if we had known about it.

• The above sentence is an example of type-3 ''if conditional clause''.  
• In type-3 ''if conditional clause'', we use ''would + have + past participle'' in the "main clause" and ''past perfect'' in the ''if clause''.

We would have done it if we had known about it.

• We would have done it = main clause
• if we had known about it = if clause

One more example:

I would have passed the test if I had studied.

• I would have passed the test = main clause
• if I had studied. = if clause