1 I found the photo by chance when I was tidying my room.
I came across the photo when I was tidying my room.
2 Fridges and freezers are not the same thing. difference
There are  difference betwwen fridges and freezers.
3 Scientists should never invent their results. made
Results should never be made by scientists.
4 Don't put those plastic bags in the bin-use
them again! away
Don't throw away those plastic bags  -  use them again!