I don’t know the reason _____ you were absent from the meeting, and I am not sure that someone will tell me the reason _____ you haven’t told me.

Are you cleaning your room–________ I ’m listening to a CD．

________ by green mountains and located at the foot of LuShan Mountain makes it a famous tourist attraction.

The trsafety seat.

－Good afternoon，class.－_____ , teacher.