The firemen did all their best to put out the fire.— excellent firemen!

The pull of gravity depends upon size, _______, upon mass. An object, whether its mass is big or small on the earth, ________in weightless conditions, like the outer space.[ ]

Kate has a beautiful _______ . Listen ! She is singing very well.

___ from other continents formillions of years, Australia has many plants and animals not found in any othercountry in the world

.—________brave Lin Tao is!—Yes, he helped his neighbour , Mrs Sun, out of fire.