詳細解釋：
past 英[pɑ:st] 美[p?st]
adj. 過去的，以前的; 結束的; 前任的;
n. 往事; 過去，過往; [語] 過去時;
prep. 超過，超出; 遠於; 越過;
[例句]In the past, about a third of the babies born to women with diabetes were lost
過去，患有糖尿病的女性生下的孩子中約有1/3夭折了。
future 英[?fju:t?(r)] 美[?fjut?]
adj. 將來的，未來的; [語法學] 將來時的;
n. 前途; 期貨; [美國俚語] 未婚妻;
[例句]The spokesman said no decision on the proposal was likely in the immediate future.
發言人說近期不會就這項提案作出決議。
look back 英[luk b?k] 美[l?k b?k]
v. 回顧; 倒退; 追憶; 回頭壹看;
[例句]Looking back, I am staggered how easily it was all arranged.
回頭壹想，我驚異地發現這壹切的安排竟是如此簡單。