An elephant weighs 3 tons;
A bag of instant noodles weighs100g;
Weight of five apples 1 kg;
A blue whale weighs 12 ton;
A bottle of drink weighs 500 grams;
Xiao Ming weighs 30 kilograms;
A cow weighs 250 kilograms;
A book weighs 500 grams.
So the answer is: grams, tons, grams, kilograms, tons, grams, kilograms, kilograms, grams.