Write the reduction reaction of aldehydes and ketones.

(N/A) The reduction of aldehydes and ketones to alcohols can be represented as follows:
Reduction of aldehydes to primary alcohols $(1^{\circ})$:
$R-CHO + 2[H] \rightarrow R-CH_2OH$
Reduction of ketones to secondary alcohols $(2^{\circ})$:
$R-CO-R' + 2[H] \rightarrow R-CH(OH)-R'$
Common reducing agents used include $LiAlH_4$,$NaBH_4$,or catalytic hydrogenation using $H_2/Ni$.