Deciding who is going to pay for the meal is usually a tricky situation. However, there are some common rules of etiquette that should be followed.
If your host invites you to a meal by saying: "I'd like to take you to dinner tonight." It is clear that he wants to pay for the meal. Your response when the bill arrives could be: "Are you sure I can't help with that?" When your host says, "No!', you express your appreciation by saying: "Thank you."
Visualize the bill setting on the table top. Your host will reach out and "pick up" the bill in order to pay it. In common usage, the person who 'picks up' the bill is the person who is responsible for paying. "Let's go to dinner tonight; my dad is picking up the bill."
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