I didn't know you were coming, so I didn't wait for you.

A.Were I to know you were coming, I would wait for you. 

B. If I had known you were coming, I would wait for you. 

C. Had I known you were coming, I would have waited for you. 

D. If I knew you were coming, I would wait for you.

Một ancol no Y có công thức đơn giản nhất là C₂H₅O. Y có CTPT là:

A. C₆H₁₅O₃

B. C₆H₁₄O₃

C. C₄H₁₀O₂

D. C₄H₁₀O