法术描述中说interposing hand飘在caster和选定的人之间，提供遮蔽。攻击对掌造成正常伤害。
能否说interposing hand也就能阻挡此人对caster做出的所有攻击？

Interposing hand creates a Large magic hand that appears between you and one opponent. This floating, disembodied hand then moves to remain between the two of you, regardless of where you move or how the opponent tries to get around it, providing cover (+4 AC) for you against that opponent.

这个看过了，我不太明白的是hand能不能挡住诸如dominate person之类的法术

单纯的掩蔽（cover）效果无法阻挡魔法，因为只有全掩蔽（total cover）效果才会使视觉连线消失，从而使固定单一目标施展的魔法无法定位。

楼主在研究较高级别法术前还是先熟读PHB其他部分比较好。