(i) `H-overset(Cl)overset(|)C=underset(H)underset(|)C-overset(H)overset(|)underset(H)underset(|)C-C-=C-H`
(ii) `{:(" "CH_(3)" "C_(2)H_(5)" "CH_(3)),(" | | |"),(CH_(3)-C-CH_(2)-CH-CH_(2)-CH-CH_(3)),(" |"),(" "CH_(3)):}`
(iii) `{:(CHO),(|),(CHO):}`
(iv) `CH_(3)-CH_(2)-CH=CH-overset(CH_(3))overset("| ")"CH"-CH_(2)-CH_(3)`