求解几道英语语法题
麻烦给翻译两个句子,解释一道题
1） I haven't gone shopping since I was ill.
2) I haven't gone shopping since I have been ill.
前两个句子的翻译总是区别不出来后边的部分
还有下面一道题也是理解不了
3）I haven't gone to school since I _____ ill.I'll go to school immediately when I recover.
A.wasB.have been
C.amD.had been
这道题跟前边两个句子很像,所以还是区分不了它们的差别