Study / is hard but interesting.
Studying is hard but interesting.
He tried / open the door, but it was locked.
He tried to open the door, but it was locked.
He's too old / to run a marathon / running a marathon.
He's too old to run a marathon.
Ben had trouble sleeping. He tried / drink warm milk with honey, but it didn't help much.
Ben had trouble sleeping. He tried drinking warm milk with honey, but it didn't help much.
My teacher suggested / read / this book.
My teacher suggested reading this book.
I'm tired of / do / the same job every day.
I'm tired of doing the same job every day.
Mike was the last / arrive at the party.
Mike was the last to arrive at the party.
He appears / understand the importance of working hard very well.
He appears to understand the importance of working hard very well.
A: Why did he go to university? B: / study languages.
A: Why did he go to university? B: To study languages.
I can't afford / buy / a car at the moment. So I travel by bus a lot.
I can't afford / buy / a car at the moment. So I'm travelling by bus a lot.