——I will come John is invited, too.——You mean if John comes you will come.
―When was the house built? ―It was built in 1949 _______ the PRC was founded.
________ is known to everybody, the moon travels round the earth once every month.
This is Mr.Smith, ________ I think has something interesting to tell you.
The school _____ my father teaches is a world-famous one, _____ was set up 100 years ago.
The most important thing _____ we should pay attention to is the first thing ____ I have said.