—Hi, Li Xiaoxia. What a surprise! Dad _____ you _______ so early. He’s upstairs reading. I’ll just call him.
He tried his best to solve the problem,________difficult it was.
Measures have been taken to prevent the river from____.
Children often display an________curiosity about every new thing they encounter.
___________in reality,the story is popular with adults.
It’s helpful to put children in a situation___________they can see themselves differently.