1.The /id/ sound is the simple past ending for verbs that end in /t/ or /d/ sounds:
decided
waited
wanted
competed
started
restarted
2.The /t/ sound is the simple past ending for verbs that end in /p/, /k/, /sh/ or /ch/ sounds:
stopped
finished
asked
liked
walked
eavesdropped
3.The /d/ sound is the simple past ending for most other verbs, such as:
lived
called
loved
trained
scored
stayed
retired
climbed
achieved
原文：http://www.cnblogs.com/shirley-ict/p/5608216.html