请妥善保管好合同，一旦遗失会很麻烦。

Qǐng tuǒshàn bǎoguǎn hǎo hétong, yídàn yíshī huì hěn máfan.

Please keep the contract properly; once it is lost, it will be very troublesome.

如果车票遗失了，需要马上到服务台补办。

Rúguǒ chēpiào yíshī le, xūyào mǎshàng dào fúwùtái bǔbàn.

If your train ticket is lost, you need to go to the service desk immediately to reissue it.

钱包遗失后，她赶紧挂失了所有的银行卡。

Qiánbāo yíshī hòu, tā gǎnjǐn guàshī le suǒyǒu de yínhángkǎ.

After her wallet was lost, she hurried to report all her bank cards as lost.