Do you know the meanings of all these sighs on the wall

Little Tom was so enthusiastic about learning Chinese and after six months, he could speak it ______ fluently.

I will ________ more effort in my studies this term.

In Britain, you ____ be 18 if you want to drive a car.

I am going to New York this evening. Is there a flight to New York then? — There ____ be a flight. But you’d better call the booking office to make sure. [ ]