–All the students in your class are in the photo ____ Susan. Why? --Aha, that is because she helped us take this photo.

 --  ______ does your sister study for the English exam?  --By asking her teacher for help. 

I like sleeping with the window open ______ it’s too cold.

—How do you like the story?—Interesting, _______ the end of it is not perfect.

—What’s the matter with you? You look so worried.-- I don’t know ___________ the problem.