选择性必修第二册;01;在空白处填入1个适当的单词或括号内单词的正确形式。

1.Anothertheorywasthatcholerawascausedbyan_________（infect）fromgermsinfoodorwater.;4.This________（tragic）castashadowontheirlives,makingthemgloomyanddepressed.;8.Thiswasthesecondtimeinternationalsportingevents_____________