选C
it 原来的事物 ,同一事物:The air in mall isn't as fresh as(_____was) before.
that 同类不同物:The air in mall isn't as fresh as_____in the park.
this 这个:this is more likely than that
选C
it 原来的事物 ,同一事物:The air in mall isn't as fresh as(_____was) before.
that 同类不同物:The air in mall isn't as fresh as_____in the park.
this 这个:this is more likely than that