He had just fallen asleep ________ the telephone rang last night.
People try to avoid public transportation delays by using their own cars, and this _____ further problems.
Although ____ my opinion, the old professor didn’t come up with his own.
The field research will take Joan and Paul about five months;it will be a long time_____we meet them again.
My parents live in a small village. They always keep candles in the house ___ there is a power cut.
It is difficult for us to learn a lesson in life _____we’ve actually had that lesson.