The license plate must be alphanumeric to be valid.

车牌必须是字母数字的才有效。

All signers must be present for the contract to be valid.

所有签署人必须在场才能使合同生效。

Crucially, the data must be accurate for the analysis to be valid.

关键地，数据必须准确才能使分析有效。

Importantly, the data must be accurate for the analysis to be valid.

重要的是，数据必须准确才能使分析有效。

Connection must be valid and open?

连接必须是有效的和打开的？

Could this argument be valid say yes- as a matter of fact this argument must be valid.

这个论点有效，说对-,实际上这个论点肯定有效。

The string must be valid PHP code and must end with semicolon.

这个字符串必须是有效的PHP代码,并且必须以分号结束.

Every record must be concurring to each other to be valid.

每个记录一定对彼此意见相同是有效的。

Original and photocopy of your passport; must be valid for at least six months.

护照正本及影印本一份，正本验毕归还。（护照效期至少六个月）

The visa for the return country must be valid for at least three months beyond the period of intended stay.

返回所在国的签证必须在指定停留期后至少三个月内有效。