1. Many people believe we are heading for environmental disaster _____ we basically change the way we live.

A. but                   B. although            C. unless        D. once

2.   The officials said the downward trend of A/H1N1 flu activity did not______ mean the worst was over. Flu activity might pick up next year.

A. greatly            B. necessarily      C. fully               D. nearly

3.  China began selling tickets for the Wuhan-Guangzhou high-speed railway, ______ boasts the world's fastest train journey with a 350km per hour average speed.