They ...................... (not, do) a pizza.
They haven't done a pizza.
I ...................... (not, be) to Paris.
I haven't been to Paris.
He ...................... (break) his leg.
He has broken his leg.
We ...................... (visit) Hà Nội 4 times.
We have visited Hà Nội 4 times.
I ...................... (eat) sushi many times.
I have eaten sushi many times.
We ...................... (not, swim) in the sea.
We haven't swum in the sea.
He ...................... (not, build) a snowman.
He hasn't built a snowman.
She ...................... (ride) a camel.
She has ridden a camel.
They ...................... (meet) Barack Obama.
They have met Barack Obama.
I ...................... (go) to the zoo twice.
I have gone to the zoo twice.