Many kinds of plants and animals are extinct (灭绝). The same thing ________ around the world.

)You can give the document to _______is in the office.However, _______to require a written paper for it.

The boy is ______ my sister, so he sits in front of her.

Most supermarkets in Shanghai have stopped free plastic bags in the past few years.

How can we protect ourselves _____ the earthquake —First, we should keep calm when it happens.