33 . 441898 June 9, the UK forced the Qing government to sign a treaty leasing 975.1 square kilometers of land in Hong Kong to the UK for 99 years. On July 1, 1997, Hong Kong returned to the motherland, and the Chinese people finally washed away the humiliation of a century. Given that July 1, 1997, was a Tuesday. Therefore, June 9, 1898, was a 
(A) Tuesday.
$(B)$ Wednesday. $\quad$ - $-2-1$
(C) Thursday.
(D) Friday.
[Solution 1] $\because 365 \equiv 1(\bmod 7)$,
$\therefore$ If $S$ represents the total number of days from New Year's Day of a certain year to the required day, $x$ represents the year, and $y$ represents the day of the year, then we have
$$
S \equiv(x-1)+\left[\frac{x-1}{4}\right]-\left[\frac{x-1}{100}\right]+\left[\frac{x-1}{400}\right]+y(\bmod 7) \text {. }
$$

When $x=1898, y=31 \times 3+30+28+9=160$,
$$
\begin{aligned}
S & \equiv 1897+\left[\frac{1897}{4}\right]-\left[\frac{1897}{100}\right]+\left[\frac{1897}{400}\right]+160 \\
& \equiv 1897+474-18+4+160 \\
& \equiv 2517 \equiv 4(\bmod 7) .
\end{aligned}
$$

Therefore, the answer is $(C)$.
[Solution 2] It is known that July 1, 1997, was a Tuesday, so it is easy to deduce that June 9, 1997, was a Monday.
From June 9, 1898, to June 9, 1997, there are 99 years, including 24 leap years.

Thus, $99 \times 365+24 \equiv 99+24 \equiv 4(\bmod 7)$.
$$
1-4 \equiv-3 \equiv 4(\bmod 7) \text {. }
$$

Therefore, the answer is $(C)$.