China's high-speed railways _________ from 9,000 to 25,000 kilometers in the past few years.
are growing
have grown
will grow
had grown
Look at the pride on Tom's face. He ____ to have been praised by the manager just now.
Professor John will give us a lecture on how to learn English, but when and where ____ yet.
He asked me how much ____ on the mountain bike.
I haven’t finished my report, but I promise I ____ it by the end of the week.
—Haven’t seen you for ages! Where have you been? —I went to Ning Xia and ____ there for a year, teaching as a volunteer.