Some verbs have an irregular past tense and participle.  A regular verb takes the ending -s, -ed, and -ing.  For example, base form "play", s-form "plays", past tense "played", ing-form "playing" and past/passive participle "played".

This, that, these, those are pointing words called demonstratives.  This and these refer to something close by or near the speaker.  That and those refer to something further away.  This and that are singular.  These and those are plural.