Dear everyone This time, I would like to know the difference between "which" and "as" used as the relative pronoun. Both can be used when the antecedent is not a noun (phrase) but a sentence. Are both of each pair correct and natural? Or only one of them is natural and correct? Perhaps, both are wrong? 1-a. You carried the luggage yourself, which was not necessary. 1-b. You carried the luggage yourself, as was not necessary. 2-a. He is a foreigner, which is evident from his accent. 2-b. He is a foreigner, as is evident from his accent. 3-a. Her feet were bare, which was the custom in those days. 3-b. Her feet were bare, as was the custom in those days. 4-a. She has married again, which was natural. 4-b. She has married again, as was natural. 5-a. Tom was not at home, which is often the case with him. 5-b. Tom was not at home, as is often the case with him. Would you tell me your intuition (and why). Thank you in advance. SIRAISI Tomio [log in to unmask]