A．One.B．Two.C．Three.D．Four.

How many generators does the shuttle carry？A．One.B．Two.C．Three.D．Four.

How many persons are in the conversation？A．One.B．Two.C．Three.D．Sour.

How many examples are there "as evidence of tribalism"？A．Four.B．Two.C．One.D．Three.

A．Two nights.B．Two days.C．Four nights.D．Four days.

How often does a person dream each night？A．Two to four times.B．Four to six times.C．Every 6

A．One.B．Two.C．Three.D．Four.