ý A.3 và 11 nha 

rút gọn ta có:
3737/5353=37/53
373737/535353=37/53
Vậy 37/53=3737/5353=373737/535353
chúc hok tốt

is listening
rains
works
is not working
is running
wants
speaks
comes
is coming
are meeting
Do you usually go - do you stay
is holding
smell
is snowing
snows
swims
doesn't run
Are you enjoying
am having
don't know
are you doing
am staying
think 
looks
live
am staying