1、解： (1)P｛只订购A的｝=P{A(B∪C)}＝P(A)-{P(AB)+P(AC)-P(ABC)}=0.45-0.1.-0.08+0.03=0.30. (2)P｛只订购A及B的｝=P{AB}-C｝=P(AB)-P(ABC)=0.10-0.03=0.07 (3)P｛只订购A的｝=0.30, P｛只订购B的｝=P{B-(A∪C)}=0.35-(0.10+0.05-0.03)=0.23. P｛只订购C的｝=P{C-(A∪B)}=0.30-(0.05+0.08-0.03)=0.20. ∴P｛只订购一种报纸的｝=P{只订购A}＋P{只订购B}＋P{只订购C}=0.30+0.23+0.20=0