haven't hadn't

在这里是haven't 还是hadn't? you must study hard if you (won't don't haven't hadn't)want if we haven't 和if we hadn't在用法上有什么不同? i ___ any books for three months.a haven't buy b hadn't buy i haven't been happy if i hadn't met you befor 句子通顺吗 haven't. hadn't you better 现在完成时否定I haven't seen it从来没有看见它I hadn't noticed 怎么一个个have 一个 We had better leave ,hadn't we 这句话有错误吗?还是haven't me 还有werent didn't haven't hadn't have和didn't have hadn't he和didn't