我差点儿没摔掉...
I was within an inch of dropping sth,bla bla bla ...
"差点儿"就是"差一点儿",
差点儿=within an inch of
按北京话说,差点儿没摔掉(没摔掉)=差点儿摔掉了(没摔掉)
According to Pekinese dialect,the meaning of "差点儿没摔掉" is just same as "差点儿摔掉了"。
Funny right?
So the meaning of the sentence of "我差点儿没摔掉...",here I give you a example and you are supposed to understand it well.
例句:我差点儿没摔掉我的iphone
Example:
I was within an inch of dropping my iphone to the ground.(As matter of fact the iphone was not dropped down luckily.)