they are talking about what can people dohow long will he come back?the meeting didn't start until all the people arrive三句话分别错在那.快
问题描述：
they are talking about what can people do
how long will he come back?
the meeting didn't start until all the people arrive
三句话分别错在那.快
答
they are talking about what can people do
about是介词，不能接从句
how long will he come back？
how long是问段时间，come back是点时间
the meeting didn't start until all the people arrive
arrive用过去式
答
they are talking about what people can do
how soon will he come back？
the meeting didn't start until all the people arrived
答
they are talking about what 【 people can】do
how【soon】 will he come back?
the meeting didn't start until all the people 【arrived】