[the machine]

first hand turn needs to be bet. youre representing an ace with your flop bet and now you check to an 8..... with the given check, its a good river call not much you can do unless you have seen him play an ace this way or slow play big hands like this. ie his check being trip 8s and hoping you bet it for him.

second is fine. thats my usual line. if villain is very aggro i sometimes check and take the pot so as not to get raised and have to muck. he may have had you kicked and now u have a better 2 pair.