今jin1 日ri4 = today
今jin1 天tian1  = today; at the present; now
美mei3 好hao3 = happy,fine,okey
明ming2 日ri4 = tomorrow
明ming2  天tian1 = tomorrow

你好,今天 我 是 美好. 明日我不是 美好.

HA! HA! I TRICKED YOU!
There is to sets of writing chinese. Traditional. Simplified.Also, words combined with other word.So forth....
你好,今天 我 是 美好. 明日我不是 美好 .
ni hao, jin rin wo shi mei hao. ming rin wo bu shi mei hao.
hello, today I am happy. Tomorrow  I am not going to be happy.
That was one way, now here is another(traditional).
你好, 今天 我 是 美好. 明日 我 不是 美好 .
See. Only some words change from traditional to simplified because they are alot. Here is an example:
不bu4 獨du2 - traditional = not only
不bu4 独du2 - simplified = not only
if 不 獨(独) = not only and 不  means negative,not , no then 獨(独) means only, alone; independent; single; sole;

UNDER CONSTRUCTION