please forum i need your help... I'd like to know if there's any difference between these two words...if the context can change the meaning or if they're interchangeable...please i need help 
Thanks beforehand
Thanks beforehand
What about this:
·I need to prepare for the testfromstarting now
·I need to prepare for the test since now
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·When you do a Review Exercise, you should start checking all the topics since the beginning.
.When you do a Review Exercise, you should start checking all the topics from the beginning.
Either of these would be acceptable but "from" the beginning would be much more common
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.My mom has been sick since Agust
·My mom has been sick from August
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these expressions are confusing to me because both choices seem to be correct...but im not really sure