下列各句中加点成语的使用，全部正确的一项是(　　)①这件事对我无异于晴空霹雳，如同一块珍藏多年价值连城的璧玉，顷刻间变成一块一文不名的瓦片。②税收是我国国民经济宏观调控的重要手段之一。在国计民生中占有无以复加的重要地位。③在《群英会蒋干中计》中，罗贯中运用生动细致的动作神态描写，为我们塑造了一个胸无城府却又自作聪明、十分迂腐可笑的蒋干形象。④这个潜伏已久的特务，平日装得一副老实相，倒也没人能看透他，哪知今天他居然赤膊上阵了，一下子露出了狐狸尾巴。⑤一旦新的董事会选出继任者，格林斯潘便将功成身退。⑥这篇文章语言清新、流畅，读后让人叹为观止，连声叫好。

One of the main themes of the summit was “sustainable development”,or the question _________ we can continue developing the world without damaging the environment.

Everything was perfect for the picnic _____ the weather.[ ]

e must have the largest number ofspeakers, ________

I’ve been considering _______ my job as a teacher because a teacher is often considered _______ a gardener.