I heard that China is a “Kingdom of bicycles”,and I know thi

前后语态不一致,前面是过去式,前面的从句又是现在式
后面也是现在式
Hear改成hear about,后者是听说,前者是听到
no exaggeration我觉得改成not exaggerated更顺一些
改成
I hear about that China is a “Kingdom of bicycles”,and I know this is not exaggerated
1楼的名字前不能用not来修饰
not+动词
no+名词,楼主的用法是对的

整体来说没有大错，但改写为：
I heard that China is the "Kingdom of bicycles" and this is not an exaggeration.
比较通顺。

I (hear)that China is a “Kingdom of bicycles”, and I know (that) is no exaggeratiON.

后半句要表达没有夸张应该用 there be 句型there is no exaggeratiON.
或者表达成这不是夸张
exaggeratiON是名词，前面要有定冠词或量词修饰
this is not an exaggeratiON
1楼的名字前不能用not来修饰？？？
常用句 i am not a girl难道是错的？
前后语态不一致,前面...

前后时态不一致。I've heard that China is a “Kingdom of bicycles”, and I know it is no exaggeration.