* Simple: I mistook the stranger for a friend.
* With a clause: I mistook the directions, which led me to the wrong place.
* In the past perfect: I had mistaken the date, so I missed the meeting.
* With a negative: I didn't mistake his kindness for weakness.
* In a question: Did you mistake the noise for thunder?
Let me know if you'd like to see some more examples, or want to see how to use "mistook" in a particular context!