33.67 The ternary expression of $x$ is
$$
12112211122211112222_{3}
$$

Then the first digit from the left in the nonary expression of $x$ is
(A) 1.
(B) 2.
(C) 3.
(D) 4.
(E) 5.
(32nd American High School Mathematics Examination, 1981)
[Solution] $x$ is a 20-digit ternary number, which can be expressed as
$$
\begin{aligned}
x & =1 \cdot 3^{19}+2 \cdot 3^{18}+1 \cdot 3^{17}+1 \cdot 3^{16}+\cdots+2 \cdot 3+2 \\
& =\left(1 \cdot 3^{19}+2 \cdot 3^{18}\right)+\left(1 \cdot 3^{17}+1 \cdot 3^{16}\right)+\cdots+(2 \cdot 3+2) \\
& =(1 \cdot 3+2)\left(3^{2}\right)^{9}+(1 \cdot 3+1)\left(3^{2}\right)^{8}+\cdots+(2 \cdot 3+2) \\
& =54 \cdots 8_{9},
\end{aligned}
$$

Therefore, the leftmost digit of the base-9 representation of $x$ is 5 (base-9 5). Hence, the answer is $(E)$.