You always be careful with electricity for safety.( )
must
can
mustn't
can't
Is that Tom over there?
It _____ be him. He is on the plane to Chengdu now.( )
might not
Sally's favorite _____ is orange.
I see.That's why all her sweaters are orange.( )
fruit
color
juice
That's the boy ____ won the first prize in the competition yesterday.( )
who
which
whom
We all look forward to ____ you again soon.( )
see
seeing
seen
Do you know ____ ?( )
how old is he
how old he is
he is how old