结合语境解释下列句子中划线的词语。

封了阳台，虽可以阻隔住城市的喧嚣，开辟出一块活动的空间，但是，这鸽子便没有了安身立命的场所。

①喧嚣

原来楼前有一块草坪，儿子曾在这块草坪上蹒跚学步。

②蹒跚

金刚石、石墨、木炭和C₆₀都是由碳元素组成的单质，下列关于碳的单质的叙述正确的是（   ）

It ____(snow)heavily last night．So I ____(ask)a few friends to the park this morning．The trees, the houses and the roads．____(be)all white．We ____(decide)____(make)a big snowman on the road．We ____(put)a carrot in the snowman's head．That ____(be)the snowman's nose．The two small black balls in his face were the snowman's eyes．Then we started ____(sing)and ____(dance) round the snowman．We ____(have)a great time today．