from memory

without reading or referring to notes

憑記憶

each child was required to recite a verse from memory.

每個小孩要背誦一節(jié)詩。

in memory of

intended to remind people of, especially to honour a dead person

紀念（尤指死者）

take a trip (或 walk) down memory lane

deliberately recall pleasant or sentimental memories

追憶