Question

The H1N1 flu spread very quickly at the beginning, __________, many people were ill.

A．therefore

B．instead

C．in advance

D．however

Answer 1

A

考查词义辨析。Therefore 因此，instead 代替，in advance 提前，however
然而，句意：H1N1病毒在开始传播的非常快，因此，许多人病了。所以选A。