专门替中国人写的英语语法1-8：特殊动词随主词的变化
规则(8)：特殊动词随主词的变化。
英文中，有些动词因主词不同而改变，verb to be是其中之一，因此，我们必须记得以下的规则：
第一人称 第二人称 第叁人称
现在式 单数 I am You are (He，She，It)is
复数 We are You are They are
过去式 单数 I was You were (He，She，It)was
复数 We were You were They were
Verb to have也有类似的变化：
第一人称 第二人称 第叁人称
现在式 单数 I have You have (He，She，It)has
复数 We have You have They have
过去式 单数 I had You had (He，She，It)had
复数 We had You had They had
