+0
Original: In general, temperatures at the South Pole average 54°C lower than the North Pole.

Some teacher said that this sentence is grammatically wrong. he said this sentence should be fixed like

fixed: Original: In general, temperatures at the South Pole average 54°C lower than 'those at' the North Pole.

does 'those' must included?(for comparing temperatures of the south pole and the north pole)
+1
dDoes 'those' must have to be included?

Yes, though you'll hear them omitted in informal conversation.
Comments  
fivejedjondDoes 'those' must have to be included?Yes, though you'll hear them omitted in informal conversation.
thanks.

I made mistakes too..lol