Whileoverallratesofsuddeninfantdeathsyndromes(綜合徵)have...

問題詳情：

 While overall rates of sudden infant death syndromes(綜合徵) have decreased in recent years, deaths from sleep suffocation(窒息) ________ over the same time period.

  A. double                               B. have been doubling       C. have doubled              D. doubled

【回答】

C

知識點：動詞時態與語態

題型：選擇題