21. Traffic is getting heavier and heavier, so people are encouraged to use more public ___________
A. route B. transport C. resource D. service
22. It wasn’t until he called my name that I _________ my old friend, who I hadn’t seen for years.
A. thought B. knew C. recognized D. believed
23. Seeing the building was falling down, the persons outside shouted___________ at the ones in it to run out for their lives.
A. right away B. right now C. now and then D. ever since
