when people talk about the cities in Australia,the first__ comes into mind is Sydney.
不好意思選成了one,選錯了。如果題目中沒有comes into mind才能選one.that才是正確的,不過看到妳的補充問題才反應過來。選that引導定語從句修飾the first,也就是說that comes into mind是作為定語修飾the first,翻譯為閃現在腦海中的第壹個城市是(悉尼)。這裏the first後省略了賓語city或one,先行詞有序數詞修飾時只能用that引導定語從句。希望能幫到妳。