2
Правило: there's and a/an употребляются с исчисляемыми существительными в единственном числе.
There are and some употребляются с исчисляемыми существительными во множественном числе.
There's and some употребляются с неисчисляемыми существительными.
3
1 There are some sandwiches.
2 There's an onion.
3 There's some coffee.
4 There's is a tomato.
5 There's some butter
6 There's some spaghetti.
7 There are some eggs.
8 There's some pizzas.
9 There's some yogurt.
10 There are some vegetables.
4
1 To make an egg sandwich you need some bread, some butter, and an egg.
2 To make a cup of English tea you need some water, a teabag, and some milk.
3 To make chips you need some potatoes and some oil.
4 To make a cup of coffee you need some water, some coffee and some milk.