The bronze script of character To Be ischaracter Morning - 早 (Post 266), the bottom one is character Foot -止 (Post 93). Go out in the morning, which is To Be. To be doing the right thing in right time, Chinese believe that the morning is the most important time for a day, people should get up early and start to work in the morning. To Be here is Should be.
The big seal script of character To Be is
Similar to bronze script.
The small seal script of the character is
The top is character Sun - 日(Post 4), the bottom one is character Straight to - 正 (Post 325). The character has changed a lot, from Morning + Foot to Sun + Straight to. There are two possibilities. One is that the small seal script was a form with writing mistake, another one is that the haracter meaning is changed to The Sun is right over people's head in summer, to be the busiest season in a year.
The clerical script of the character is
The pinyin of character 是 is Shi4.
The character became To Be, a very popular character, the only To Be in Chinese. Chinese say I 是，you 是，he 是，we 是，they 是，I yesterday 是, you tomorrow 是, etc. No matter what the personal pronoun is, what the tense is, all "是". So Chinese grammar is much easier than that of English. You may have noticed that Chinese often make mistakes in To Be: I am there yesterday, He is a good student in college 10 years ago, We are better tomorrow, etc. Because Chinese just use 是 for every personal pronoun , and tense.