СОСТАВИТЬ ПРАВИЛЬНОЕ ПРЕДЛОЖЕНИЕ

1) there is very little money in my bank account but there's quite a lot in my sister's

2) how much money have you got on you? I'm afraid I haven't got some

3) much people don't complain when they should.

4) there isn't money enough in my bank account to go on holiday this year.

5) she paid one hundred thousand of pounds for it.

6) my two brothers are older than me. one is eighteen, the second is twenty-one.

There is very little money in my bank account, but there is quite a lot in my sister’s.
Предложение было почти правильным. После my sister’s подразумевается bank account.

How much money have you got on you? I’m afraid I haven’t got any.
В отрицательных предложениях обычно используется any, а не some.

Many people don’t complain when they should.
С существительными, которые можно посчитать, употребляется many, а не much: many people.

There isn’t enough money in my bank account to go on holiday this year.
Существительное ставится после enough: enough money, а не money enough.

She paid one hundred thousand pounds for it.
После числительных hundred, thousand, million предлог of не нужен, если названо точное количество.

My two brothers are older than I am. One is eighteen, and the other is twenty-one.
Когда говорится только о двух людях или предметах, естественнее использовать the other, а не the second.