So what you do is to introduce some kind of a V7 - I relationship when you go to the second line.
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听一听效果:你加了一些压力到这一段的最后三拍上,这种压力只有你在换到第二段的属七和弦时才得到解决。
Listen to the effect: You put some tension to the last three beats of the line , and that tension is not resolved before you change to the IV chord in the second line .