Either you or I ___ invited to the important meeting.
When we went into the park, we saw someone _____ Chinese Kungfu.
Lisa used to ________the bus to go to school,but now she is used to ________there.
Students should learn how ________ problem.
—Why is Linlin practicing speaking English? —________ abroad for further study.
—Why are you so excited today? —We were told ________ a picnic this weekend.