You form the past participle of regular verbs by removing the ending -en from the infinitive, ie. the dictionary form, and then adding ge- to the beginning and t to the end:

 Try guessing the right forms before displaying the answer hören to hear
sagen to say
kaufen to buy
gehört heard
gesagt said
gekauft bought

The word order in sentences with the past is different from English. The past participle in German appears at the end of the sentence.

Ich habe eine Tasche gekauft. I've bought a bag.

In some past participles you have to add -en at the end, or just leave the verb as it is in the dictionary form. The verb can change as it does in English, eg. sing/sung, drink/drunk:

 Try guessing the right form before displaying the answer singen to sing
lesen to read
trinken to drink
kommen to come
Ich habe gesungen I've sung
Ich habe gelesen I've read
Ich habe getrunken I've drunk
Ich bin gekommen I've come

Verbs beginning with ver- don't take ge- at the beginning, but keep the ver-. However, in some cases it is followed by a vowel change.

 Try guessing the sentences before displaying the answer
verlieren to lose
vergessen to forget
Guess the sentence I've lost my bag.
Guess the sentence Where did you forget your bag?
verlieren to lose
vergessen to forget
Ich habe meine Tasche verloren. I've lost my bag.
Wo haben Sie die Tasche vergessen? Where did you forget your bag?

When you learn German verbs it makes sense to memorise the way they change when put into the past as well.