I met an old friend in the back store yesterday .

问题描述:

I met an old friend in the back store yesterday .
改成强调不同成分的强调句,至少三句!求救!

it was yestoday that I met an old friend in the back store ;
it was an old friend that i met in the back store yesterday .
it was in the back store that i met an old friend yesterday .