Valentine greetings were popular as far back as the Middle Ages (written Valentine's didn't begin toappear until after 1400), and the oldest known Valentine card is on displa at the British Museum.

情人节的祝福早在中世纪时期就已经很受欢迎了（手写的情人节礼物直到1400年之后才出现），而已知的最古老的情人节贺卡在大英博物馆中展出。

youdao

The cover layout of science & technology periodicals should follow the principles of standard of editing form, expression of science & technology contents, reflection of image identification, displa…

科技期刊封面设计必须遵循符合编排格式规范的原则、体现科技内涵的原则、增强形象识别性原则、追求视觉美观性原则。

youdao