题目

In 2004，the World Health Organization，WHO，warned of a possible outbreak of another serious disease which may be even more deadly than SARS．The WHO believes that it is likely that bird flu will spread to human beings in the next few years．If it does，up to seven millions people could die from the disease． Diseases like bird flu are caused by viruses，that is，tiny things which change and become more dangerous over time．When a new type of a common virus changes，it may be able to get past the body’s immune(免疫的)system．If that happens，humans are in great danger until —______ can you improve your English so quickly? —By ______ tapes every day. A. What, listening to B. How, listen to C. What, listen D. How, listening to