过去式加 -ed 的读音
1、在清辅音后,读清辅音 / t / .
worked / kt / helped / pt / passed / st /
washed / t / watched / t /
2、在浊辅音和元音后,读浊辅音 / d / .
played / d / carried / id / answered / d / 
lived / vd / used / zd / called / ld /
3、在 / t,d / 音后面,读 / id / .
wanted / tid / needed / did