--have you ever been to Beijing before?--No. it is the first time that I ____here.
It used to ______ that humans and animals were different and had little in common.
The day breaks, _______ the birds are singing.
________, I attended the meeting instead of him last week.
When you read the book, you’d better make a mark ______ you have questions.
I didn’t see your sister at the cinema. If she ______, she would have met my brother.