1. Given $\mathrm{i}$ is the imaginary unit. Then the complex number $\frac{1+2 \mathrm{i}}{\mathrm{i}-2}=$ ( ).
(A)i
(B) $-\mathrm{i}$
(C) $-\frac{4}{5}-\frac{3}{5} i$
(D) $-\frac{4}{5}+\frac{3}{5}$ i
\begin{array}{l}\text {-1. B. } \\ \frac{1+2 \mathrm{i}}{\mathrm{i}-2}=\frac{(1+2 \mathrm{i})(\mathrm{i}+2)}{(\mathrm{i}-2)(\mathrm{i}+2)}=-\mathrm{i}\end{array} 

The translation is:

\begin{array}{l}\text {-1. B. } \\ \frac{1+2 \mathrm{i}}{\mathrm{i}-2}=\frac{(1+2 \mathrm{i})(\mathrm{i}+2)}{(\mathrm{i}-2)(\mathrm{i}+2)}=-\mathrm{i}\end{array} 

Note: The mathematical expression is already in a universal format and does not require translation. The text "B." is kept as is, assuming it is a label or identifier.