(A) 'Stationary' is 'not moving'; 'stationery' is writing and other office materials. (A) 'Prostate' is a gland; 'prostrate' means 'lie down stretched'. (A) 'Mantle' is a cloak or covering; 'mantel' is a shelf. Behind the covering of sternness lies the heart of gold. (B) 'Lightening' is something that lightens a burden. 'Lightning' (natural electrical discharge) accompanies thunder; the keyword is 'strike'.