How to control the speed of "Scale" change?

[HuaLi]

You need to change scale timing to continuous. 
You don't need to make timing on the scale parameters, because after 130 frames, particles are already there. 

Attaching you file. 

You are doing pretty well, but you need to watch out and understand "timing" option in the scale, and other operators.

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forgot to attach

Thanks, but I don't understand why the scale change does not occurs between 130-190 frame, but other scope of frame.