完成句子The flu believed(                    )byviruse that like to reproduce in the cells insid the human nose and throat.(cause)本次流感被认为是由一种病毒引发的,它能在人体鼻腔与咽喉内进行自我繁殖.   2.（               ）is why the dinosaurs suddenly disappeared 65million years ago.(remain)        65亿年前为何恐龙突然灭绝仍然是一个迷.   3.The road is covered with snow.Ican't understand(　　　）going by moorbike this moring.(insist)        道路上覆盖着积雪,他们却仍然坚持骑摩托车出行,我实在不能理解其中原因.

完成句子
The flu believed(                    )byviruse that like to reproduce in the cells insid the human nose and throat.(cause)
本次流感被认为是由一种病毒引发的,它能在人体鼻腔与咽喉内进行自我繁殖.
   2.（               ）is why the dinosaurs suddenly disappeared 65million years ago.(remain)
        65亿年前为何恐龙突然灭绝仍然是一个迷.

   3.The road is covered with snow.Ican't understand(　　　）going by moorbike this moring.(insist)
        道路上覆盖着积雪,他们却仍然坚持骑摩托车出行,我实在不能理解其中原因.