Mom came to Emily's room and found the window was open. It was raining hard outside. Because the window was opened, the books on the desk were wet.

A: Emily, look at the books. They are all wet.

B1:Oh, no. I'm sorry. I forgot to close the window.

B2:Oh,dear. I'm sorry, Mom. I didn't close the window.

B3:Oh, boy. Excuse me, Mom. I kept the door open.
(Are the answers all grammatical? What other expressions can we use? Common ones, please. Thank you.)

B4:

B5:

B1 and B2 are fine.

B3: Oh, boy. Excuse me, Mom. I left the door open.

B4: Oh, no! I forgot to close the window. I'm so sorry, Mom.

B5: I'm so sorry, Mom. I forgot to close the window.

All of the given answers are grammatically correct and can be used in this situation to apologize for leaving the window open. However, B3's response does not directly address the issue of the wet books, so it may not be as appropriate in this situation. Here are a few more common expressions that can be used to apologize in this context:

B4: I'm really sorry, Mom. I should have closed the window.
B5: I apologize, Mom. It completely slipped my mind to close the window.

Hope these examples help!