Questions 11 to 18 are based on the conversation you have just heard.

A．The speaker’s friend entered his house from back door.
B．The speaker’s friend entered his neighbor’s house by mistake.
C．A thief entered the speaker’s house by mistake.
D．The speaker’s friend entered the room by climbing the apple tree.

A．The history of Benjamin Franklin.
B．The history of the U.S. mail.
C．The Changes of writing letters.
D．The history of U. S.