I don't suppose (that) anyone who are present at the meeting will volunteer to join the team,will they?
这是否定前置.一般这几个词常用否定前置：think,suppose,expect,believe .
因为主句是第一人称时,反问句一般会反问宾语从句,所以,跳过who are present at the meeting 定语从句,anyone will volunteer to join the team,后面又是will they,所以,主句一定是个否定形式.