Question

One must take a bath every day.
Begin: One cannot but .......​

Answer 1

Answer:

Your answer is-

''One cannot but bath everyday.''

Extra: If the beginning: One cannot help........

Then the answer will be-

"One cannot help bathing everyday."

Hope this will help you.....

Answer 2

ONE CANNOT BUT TAKE A BATH EVERYDAY

[But here is used in a context of except or exclude, therefore the sentence can be reframed as "One cannot exclude taking a bath everyday"]

One must take | a |bath every day

to be changed         common

HOPE THAT HELPED YOU ;)