Seeing the happy scene, a lot of sweet memories ________.[ ]

he Internet is of great help, Idon’t think it ‘s a good idea to spend too much time on it.

He said l5 people_______，two of them_____to hospital．

The fire went on for quite some time_______ it was brought under control.

Researchers are now conducting hibernation experiments and can use chemicals to put living cells into sleep-like state they don’t age.