Chengdu has _______traffic that all the schools in it had a day off on the first day of the Western China International Economy and Trade Fair (西博会)to avoid traffic jams.
30. They appeared ____ me, so I had to explain to them.
29. The _____ of freshwater brought about a lot of difficulties for those living on the island.
28. The Chairman thought ______ necessary _____ Professor Smith to speak at the meeting.
27. The problem he put forward at the meeting was _____. Which one of the following is “WRONG?”
26. Don’t all speak at once! _______ please.