It's dangerous to swim here.look at the sigh.OH ,I ________notice it.didn't 还是haven't why?

来源:学生作业学帮网 编辑:学帮网 时间:2024/07/05 06:23:22

It's dangerous to swim here.look at the sigh.OH ,I ________notice it.
didn't 还是haven't why?

didn't
didn't过去不知道
haven't到现在还不知道(与语境不符)