what is the past particle of kneel?

Answer 1

The four principal parts of any verb are as follows:

present (walk)
simple past (walked)
past participle (walked)
present participle (walking)

I'll give you two more examples:

pray, prayed, prayed, praying
become, became, become, becoming

So ... how will you fill in these blanks?
kneel, ____, ____, kneeling

Answer 2

Check this definition for two correct past participles of kneel.

http://dictionary.reference.com/browse/kneel