serve|served|serves|serving

这个盒子可以当作一个玩具箱。

This box can ___serve as a toy box.

这部纪录片很有趣，但也具有教育目的。

The documentary is entertaining but also ___serves an educational purpose.

这间备用卧室也用作书房。

The spare bedroom also ___serves as a study.

他担任市长五年。

He ___served as mayor for 5 years.

他一直想为他的国家服务。

He always wanted to ___serve his country.

她决定在军队服役。

She decided to ___serve in the army.

这名罪犯因该罪行正在服六个月的刑期。

The offender is ___serving a six-month sentence for the crime.

在服刑期间，他完成了学业。

While ___serving a prison term, he completed his education.