Question

1. When H7N9 bird flu first appeared, people didn't know__________ doctors could cure it.

A. if      B. that C. what     D. why

Answer 1

  1. A考查宾语从句的引导词。句意：当H7N9禽流感首次出现的时候，人们不知道医生是否能够治愈它。if"是否"，故选择A。