Choose the correct forms to complete the sentences

My grades in English are [ ] than in Maths, but my Russian grades are [ ].

1. My present is [the biggest|bigger|big] than my sister's, but my brother's present is [the biggest|bigger|big].
2. My mum is [old|the oldest|older] than me, but my grandma is [old|the oldest|older] person in our family.
3. June is [the hottest|hot|hotter] than May, but July is [hotter|hot|the hottest] month of the year.
4. It's [darker|the darkest|dark] in the evening than in the afternoon, but the night is [the darkest|darker|dark].
5. My grandma's pancakes are [tastier|the tastiest|tasty] than my aunt's, but my mum's pancakes are [the tastiest|tastier|tasty] in the world!