Thesehotspotsaresignificantbecausetheyallowustolocatekeyareasforfocusingeffortsatconversation.

雅思聽力這句話，為何是focusing effortsatconservation而不是on呢?

These hotspots are significant because they allow us to locate key areas for focusing efforts at conversation.

非常簡單的道理，at 跟 efforts 搭配，表示“在...方面的努力”。不跟 focus 搭配，該動詞可單獨用，不必肯定與 on 連用。

efforts at conversation：“在談話方面的努力”。介詞短語作定語。

更多例句：

He came up with some awkward attempt at conversation.

他走過來笨嘴拙舌地搭訕了幾句。

After some stilted efforts at conversation, he gave up and left.

在作了一番勉為其難的談話嘗試之后，他不再交談下去，離開了。

After several attempts at conversation, Moses shyly asked, do you believe marriages are made in heaven?

試著開了幾次口之后，摩西怯生生地問道“你相信婚姻是上天注定的嗎？”

Elizabeth was determined to make no effort at conversation with a woman who was being more than usually rude and disagreeable.

伊麗莎白感覺這個女性比平常更無禮傲慢，讓人討厭，于是拿定主意，不先開口跟她說話。