(N/A) The Lewis structures are drawn by representing valence electrons as dots and bonds as lines:
$1. H_2S$: Sulfur is the central atom with two lone pairs and two $S-H$ single bonds.
$2. SiCl_4$: Silicon is the central atom bonded to four chlorine atoms by single bonds,with each chlorine atom having three lone pairs.
$3. BeF_2$: Beryllium is the central atom bonded to two fluorine atoms by single bonds,with each fluorine atom having three lone pairs.
$4. CO_3^{2-}$: Carbon is the central atom bonded to three oxygen atoms. One oxygen is double-bonded to carbon,and two are single-bonded with a negative charge,with all oxygens having lone pairs.
$5. HCOOH$: Carbon is the central atom bonded to one hydrogen,one oxygen (double bond),and one hydroxyl group $(-OH)$.