Example sentences
nǐ你shì是xué学shēng生ma吗？
Are you a student?
zhè这shì是duì对de的。
This is correct.
The story behind the character
是
日 (sun) over 正 (straight). Xu Shen wrote 是, 直也: "to be straight." The sun at high noon, dead center, not leaning. That was 是. It only later became the verb "to be." So 是 started as "straight," not "is."