to fill / to satisfy / to fulfill / to act in place of / substitute / sufficient / full
充
=
亠
+
允
:
Mnemonic symbol: a charger for your mobile phone. Chantal Chicken (chu) has to charge her mobile phone, but the only charger (充) is outside in front of the engine ((e)ng1). Without any better option she waits outside in the cold wind for her phone to charge until she gets a runny nose (允). Lacking tissues she has to blow her nose into her beret (亠).
氧
=
气
+
羊
:
Maud Younger (y) gave the sheep (羊) a balloon (气) inside of the anglepod (ang3), but unfortunately it doesn't float because it is filled with oxygen (氧).