That ______be an alien﹣there's no such thing!( )
might
must
can't
Thank you for telling me so much knowledge about nature.
Don't mention it. ______ you have more questions, come to me any time.( )
If
Because
Though
There is someone knocking at the door.
It must be the repairman. I ______ him to come to fix our fridge two hours ago.( )
call
have called
called
______ exciting the news is! Beijing will hold 2022Winter Olympic Games.( )
How
What a
What
Julia, your mobile phone is ringing.
Wait a minute. It's dangerous ______ it while crossing the street.( )
answering
answer
to answer
Look, what an old bridge! It looks so special!
Yeah, it ______ nearly 500 years ago.( )
was building
was built
has built