They didn’t go home ________ they finished their work.
句意：他们直到完成工作才回家。
考查从属连词辨析。because因为；where在……的地方；until直到……；while当……时候，由否定形式“didn’t”和句意，可知本句用句型not…until，这种否定形式表达的意思是“直至某时才做某事”，即“直到完成工作才回家”，故选C。
They didn’t go home ________ they finished their work.
—What do you feel ______ you are looking through the old pictures?
—How time flies!
We will make fewer mistakes _______ we are careful enough.
— Which do you prefer, tea or coffee?
— Either. ________ tea ________ coffee are my favorite.
Work hard, _________ you will get good grades.
—Excuse me. Where is the nearest hotel?
—Just go down this road ________ you see a library. It’s across from it.
President Xi encourages all Chinese people to plant trees______ our country can be greener and more beautiful.
It was great in the end ______ we had a terrible time at the beginning.
—Peter, would you like to go shopping with me?
—I'd love to, ________ I have to finish my homework first.
In Chinese families, people won't start dinner ________ the elders take their seats.
