As you get older, your _______ towards the matter will change.

 —Jack can't concentrate on his lessons recently.—Yes, that might ____ why he did so badly in the last test.

 Many teenagers feel lonely, __________ no one understands them and the changes they are going through.

When he opened the box, it ____________ a bad smell.

I dropped my keys in the grass, but luckily Kate _______ them.