7, Radio and television have made it possible for advertisers to capture the attention of millions of people in this way.

make it possible for sb to do sth 使……可能

Eg.: His fwe material possessions make it possible for him to move from place to place with ease.

    The money he won made it possible for him to make a tour around the world

8, The response to this competition was tremendous. Before long, biscuits of all shapes and sizes began arriving at the factory.

responce = reaction: 反映

before long = soon, shortly

biscuits of all shapes (sizes ), shoes of all sizes

9,  It seemed certain that this would win the prize.

.It seemed certain that...

注意：用it 做形式主语表示肯定时，要用certain,而不能用sure.新概念英语官方网站

We are sure / certain...

It is certain...