Compared with the generation of our grandparents, who grew up in an age when people were lack of almost every kind of materials, we should be content with the ____ supply.

Honey, it’s your turn __________ the dishes.

His determination and devotion to science________his great discovery.[ ]

______ of years later, the first extremely small plants began to appear on the surface of the water.

When _______ help, one often says “Thank you.” or “It is kind of you “