Mike and Jim's room is tidy, ______ their sister's not.
句意：迈克和吉姆的房间很整洁，但是他们妹妹的房间不整洁。
考查连词辨析。but但是；and和；or或者。根据Mike and Jim's room is tidy“迈克和吉姆的房间很整洁”及their sister's not“他们妹妹的房间不整洁”，可知，两句之间是转折关系，所以空格处填but。故选A。
Mike and Jim's room is tidy, ______ their sister's not.
Our English teacher is nice and patient she is very strict with us.
Even if we learn something well, we will forget it ______ we use it.
Wash your hands before meals, ______ you may get ill.
—Who went to the graduation party last night, Mary?
—Almost everyone did. ______ lots of students _____ Ms. Wang appeared at the party.
Restaurants must stop offering free plastic bags in Beijing _______ customers ask for them.
—Tim, our foreign teacher Ms. Green will go back to England next week.
—Really? Let's have a party to say goodbye to her ______ she is free this weekend.
______ you keep moving, you'll never reach the top of the mountain.
—Do you know the traffic rules?
—Sure, one of them is that we can’t go across the street _____ the light is green.
I waited ______ they finished talking.
