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\newtheorem{eg}{例~}
\newtheorem{ex}{~}
\newtheorem{rem}{注~}
\newtheorem{thm}{定理~}
\newtheorem{coro}{推论~}
\newtheorem{axiom}{公理~}
\newtheorem{prop}{性质~}
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A.~#1\\
B.~#2\\
C.~#3\\
D.~#4
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C.~#3& &D.~#4&
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(1)~#1& (2)~#2\\
(3)~#3& (4)~#4
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A.~#1 &B.~#2& C.~#3& D.~#4
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\newcommand{\varfourch}[4]{\par\begin{tabular}{p{.23\linewidth}p{.23\linewidth}p{.23\linewidth}p{.23\linewidth}}
(1)~#1 &(2)~#2& (3)~#3& (4)~#4
\end{tabular}}
\begin{document}

<<待替换1>>

\end{document}