Tell you a funny thing that in the first sentence I make a mistake but that mistake is finally the correct. In my document , It is :
Because it is often dependent of the conditions of crystallization,
But I write : Because it is often dependent of the conditions of crystallization,...
The Wrong becomes right and that's why I can't complete this sentence. Maybe, next time, I must beware of TOEFL test documents which have a lot of typos.