1.My friend gave me his picture as a memento before going away.

1.我的朋友在离别前给我一张照片留作纪念。

2.They gave him a watch as a memento of his time with the company.

2.送了一块手表作公司服务的纪念。

3.The director will be presented with a memento for his long years of service.

3.公司效力多年将获赠予纪念。

4.That's how the phrase memento mori should be read: don't forget to die!

4.也就是说“mementomori”这个拉丁短语应该被读作：谨记死亡！