When there is a fire,we have to learn＿＿＿ to call
问题描述：
When there is a fire,we have to learn＿＿＿ to call
When there is a fire,we have to learn ＿＿＿ to call the fire ststion and ＿＿＿ to do．
A．how；how B．what；how
C．what；what D．how；what
答
D 翻译一下句子,应该就可以理解了吧.
当起火的时候,我们必须学会（how）怎么打火警电话和要做什么（what）.