The number of air crashes that _______ in developing countries _________ increasing.

What do the letters “DOS” ______？—Disk Operating System.

下列各组句子中，加横线词的词类活用现象相同的一组是（ ）

So clearly ______ that I was able to understand much of what he said. [ ]

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（ ）十月底了，_______，_______，________，________，_________，_________，好像背着火炉在走。①蜿蜒起伏的石阶宛如大海抛出的一条长长的浪花，在山中明亮地闪烁着②而石阶暴露在草木稀疏的向阳山坡上时③香港的太阳仍然火辣辣的④能缓释行山时的疲劳⑤遇到林木茂盛的地方，就有难得的阴凉⑥脊背就有被灼伤的感觉