10: nadie me los da (i’m pretty sure it’s asking to you (te) who gives you the gifts? so you would respond with me )
12: sí nos comemos (comer is conjugated to the nosotros form, so the pronoun would be we (nos)
16: comerlo (it’s taking about lunch which is masculine)
17: estoy hacerlo (ejercicio is masculine)
18: estoy comerla (comida is feminine and comiendo is the same thing as eating and comer is to eat)
19: ella levantarlas
20: mi hermano nunca comerlas