The letter is not dated so we can't tell when it was written.

这封信没有注明日期，因此我们不知道是什么时候写的。

youdao

This inoculation certificate against yellow fever was not dated.

防黄热病注射证书过期。

youdao

Participants are allowed to send at the most 5 different bookplates, not dated earlier than 2010.

参加者允许有最多5个藏书票作品日期不能早于2010年。

youdao

In fact,Mister Obama told the gathering that Michelle probably would not have dated him if they had not agreed on Stevie Wonder.

VOA: special.2009.03.13

The typescript is not dated but bears the address Old Thatch, Bourne End, Buckinghamshire - Blyton's home until 1938.

BBC: 'Lost' Enid Blyton book unearthed

The deadline for comments was due to be 2 July, but notices put up on the pay phones were not dated and some were not put up at all.

BBC: New consultation over phone boxes

The finger bone was found in strata dated to between 48, 000 and 30, 000 years ago (the bone itself has not yet been dated).

ECONOMIST: A new species of human