规则动词的过去式、过去分词变化是否加-d或-ed。例如finish——finished（规则动词）
不规则动词的变化：不是加-d或-ed。例如eat——ate（不规则动词）。
l Regular VerbsandIrregular Verbs
A regular verb (also known as a weak verb) forms its past tense and past participle by adding -d or -ed (or in some cases -t) to the base form: "We finished the project."
