The following is the last part of chapter 6: Ralph says, "There's no signal showing. There may be a ship out there. Are you all off your rockers?"

Mutinously, the boys fell silent or muttering. Jack led the way down the rock and across the bridge.

What might this foreshadow?

the following key ideas correctly express the key sentence.

restate key idea: most people can learn to swim in ten short lessons.

restate key idea: the majority of water-accident victims require mouth-to-mouth breathing.

restate key idea: an empty, tightly closed gallon jug will support a tired swimmer.  

restate key idea: first aid is to prevent accidents as well as assist in rescue.

explanation: the key idea needs to have the same topic as the key sentence (drowning and safety).

that’s a nice boss :