The police asked him to _________what he had seen.

Now there is a danger ________ the groundmay fall in under the heavy traffic

依次填入下面一段文字横线处的语句，衔接最恰当的一组是（ ）在世界各国建筑史上，石质材料都有广泛而久远的应用。________，________，________，________。________，________。石质文物的形式丰富多样，我国著名的四大石窟均被列入世界文化遗产名录。①成为研究历史的重要文物 ②承载着丰富的历史信息③完好保存至今的古建筑多为石质 ④石质文物占有极其重要的地位⑤它们经历久远的历史年代 ⑥在我国历史文化遗产中

Detective Sam Peterson told the journalists ________ they hadn’t dismissed the idea that Justin was taken away by the aliens, they were looking into other possibilities.

“Not all birds can fly”means ．