Period of contract
[經] 契約(合同)有效期間
?? 詞語組成解析
period
['p?r??d]
n. 時期;（一段）時間;學時;句號;
adj. 具有某個時代特征的;（關于）過去某一特定歷史時期的;（家具、服飾、建筑等）某一時代的;
peri周圍，靠近+od道路→周期
of
[?v]
prep. 關于;屬于…的;由…制成;
aux. 助動詞 [非標準用語、方言] =have [主用于虛擬語氣];
??? 情景例句
Rome wasn't build in a day.
偉業非一日建成。
A great ship asks deep waters.
大船要走深水，蛟龍要在海中游。
He had known that it was not safe to travel alone in the forest near the coast.
也聽說過獨自一人在海邊的森林里走是不安全的。