How long did it take to develop the game in total

A．The speaker used to think writing is more important than teaching.
B．The speaker used to think writing is less important than teaching.
C．The speaker realizes through experience that the best author is always the best teacher.
D．The speaker still believes that writing is more important than teaching.

A．Climate change could be caused by mostly natural forces.
B．Today greenhouse gases are the largest human influence on global climate.
C．Climate change is truly a global issue, but it can’t prove to be the greatest challenge to us.
D．Carbon dioxide levels in the atmosphere have fallen by 31 percent since preindustrial times.