我已经在手机里的日历标记了她的生日。

Wǒ yǐjīng zài shǒujī lǐ de rìlì biāojì le tā de shēngrì.

I've already marked her birthday in my phone's calendar.

我在我的纸杯子上面写了我的名字作标记。

Wǒ zài wǒ de zhǐ bēizi shàngmian xiě le wǒ de míngzi zuò biāojì.

I wrote my name on my paper cup as a label.

太空人在月球上插上国旗以作登陆的标记。

Tàikōngrén zài Yuèqiú shàng chā shàng guóqí yǐ zuò dēnglù de biāojì.

Astronauts planted a national flag on the moon as a marker of their landing.