instruction:
Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
question:
10 million years long can a large star be on the main sequence stage.
answer:
How long can a large star be on the main sequence stage?


question:
Covalent solutes separate into individual molecules when dissolved.
answer:
Covalent solutes separate into what when dissolved?


question:
Gases and liquids become solids at low temperatures.
answer:

When do gases and liquids become solids?