whAt wAs thE importAnt EvEnt in DECEmBEr 19797
A．ChinA switChED From stAtE plAnning AnD isolAtionism to rEForm AnD thE opEn-Door poliCy.
B．ChinA AppliED to join gAtt.
C．ChinA BEgAn to nEgotiAtE with thE us pArty in orDEr to mAkE thE Entry For gAtt.
D．ChinA DECiDED to join thE worlD' s prinCipAl trADing BoDy.