If you have trouble pronouncing the word, you can repeat it over and over again _______ you are comfortable with it.
This is the topic _______ we are talking about now.
Mrs. White doesn’t know her friend _______ to Beijing. If she _______ here, she will meet him at the station.
Chinese is one of ______ subjects in our school.
I was watching TV ______ my mother was writing an e-mail to her friend.
We must study hard so that we can get a good job when we ________.