These verbs take a GE- prefix in the past tense. They do not have another prefix already on the root, and there are not two roots forming one word, like under+stand = understand. So, it would be a verb like STAND.
Ek staan in die water. (present)
Ek sal in die water staan. (future)
Ek het in die water gestaan. (past)
Ek WIL in die water staan. (modal)
Make it future or past tense.
Make any of these sentences above a question or as a negation.