I don't expect u do that!!!!
look! no preposition, this is a problem of young English learners .They often search for some preposition, checking verbs in Oxford Dictionary or any other monolingual ones can be very helpful in these cases.
(I expect) informal used to indicate that one supposes something to be so but has no firm evidence:they're just friends of his, I expect[with clause] :I expect you know them?
Student or Learner