If you want ________ your pronunciation, keep on practicing every day.
improve
improved
improving
to improve
The boy has _______ questions to ask his teacher in every class.
It’s not safe(安全的) for an ________ child to swim in the river.
He really likes English and often ______ English after class.
There are ______ students in our school.
There ______ a bank and two pay phones near here.