按正确顺序排列下列句子。 ( ) First, make a big ball of snow. ( ) Third, make a smaller snowball than the second and put it on the top. ( ) Let's make a snowman. ( ) Then make a face and a nose on the snowman. ( ) And at last (最后), put two sticks for his arms. ( ) And then, put some little rocks for his mouth and eyes. ( ) Second, make another small snowball and put it on the big one.