Final answer:
In the given line from a play, the term 'you' refers to the person whom 1. the speaker is instructing to join him in hiding behind an arras to observe an event concerning his daughter.
Step-by-step explanation:
The line 'At such a time I'll lose my daughter to him;/Be you and I behind an arras then...' is from a work of drama. In this line, 'you' refers to the person the speaker is currently addressing and planning with, which would typically be a confidant or an accomplice, and not any of the other options listed. This 'you' is neither the speaker (1) nor the daughter (2) nor the arras (3) nor the person the daughter will be lost to (4). The speaker instructs this confidant to join him in hiding behind an arras, which is a type of heavy curtain or tapestry, to overhear or witness an event concerning his daughter and another person.
In the line 'At such a time I'll lose my daughter to him;/Be you and I behind an arras then...', 'you' refers to the speaker.
This line is from the play Hamlet by William Shakespeare. In this context, the speaker is expressing their intention to hide behind an arras (a wall hanging) together with the person they are addressing as 'you' when they lose their daughter to someone else. The 'you' here is referring to the person the speaker is speaking to or addressing, and in this case, it could possibly be a trusted friend or confidant.