—China’s high-speed railway technology ________ the world now.
—That’s true. It has developed rapidly over the past years.
led
was leading
is leading
will lead
____________ they are brothers, they look like each other.
He is ________ to make money to help his parents live a better life.
---Andy, you were the only person that was late for the meeting, why? ---Sorry, sir. But I really had a __________ time finding the meeting hall.
—Will people live to be 200 years old? —____________.
--- Look at ______ book on the desk . Is it ______ useful one ? --Yes, it is . In the book there is much advice on how to learn math well.