．No one knows exactly when our ancestors started talking，but new evidence suggests  _______might have happened a long time ago．

—Would you like______ to eat ?—Yes，please.

— Mum, can I have         to eat? I’m hungry.—You can get some in the fridge.

When you go outing with your sisters, you must see to ________ that they are safe.

You don't have to share the umbrellas. I'll give you one_____.