• That's very interesting.
  OR:
  
• It's very interesting.
  OR:
  
• I find that very interesting.

If you want to use interest as a verb, rather than interesting as an adjective, you would need to say:

• That interests me a lot.
  
  
• That doesn't interest me very much.

-ing adjective or -ed adjective?

Remember: people might be interested in something and it is the thing itself that people find interesting. Other adjectives describing emotions follow a similar pattern:

Compare the following:

• His explanation was confusing. Most students were confused by it.
  
  
• I was disappointed not to get the promotion I deserved. A disappointing day, yesterday.
  
  
• I'm starting a new job and I'm quite excited about it. I think it will be quite exciting.
  
  
• The news was shocking. We were shocked when we heard that everyone had drowned.
  
  
• Everybody was surprised when Jenny came top of the class. It was really amazing!
  
  
• It was a tiring day. I was dead tired after all that shopping.

Note that people can also be adjective -ing, if they awaken this emotion in others:

A: Frank is such a boring person, isn't he? I find his conversation really boring.
B: He may be boring, but at least he's not as annoying as Ben who sniffs all the time.
A: Paul's an amazing guy, isn't he? He amazes me. He can always see the funny side of things.
B: I'm quite amazed by all the things Paul gets up to, I must say!

interested / disappointed / surprised / pleased + infinitive clause

Note that some of these adjectives are often followed by an infinitive clause:

• I shall be interested to hear about how you get on in Cairo.
  
  
• We were most surprised to see Kevin and Henry holding hands at the bus stop.
  
  
• I must say we were disappointed to learn that he had abandoned his job.
  
  
• I shall be pleased / delighted to accompany you to the exhibition on Thursday.
  

Interested in / surprised by / pleased with / etc

Note that if you are using a prepositional structure with these adjectives, it will normally be either with or by, sometimes both are possible. Interested, however, is usually followed by in. Compare the following:

• We were pleased / delighted with all the wedding presents we received.
  
  
• We were surprised by his rudeness at the family gathering. Quite disgusting!
  
  
• I was quite disappointed with / by the film. He's normally such an exciting director.
  
  
• I would be interested in working in Britain if I could get a work permit.
  

Interest / surprise / please / etc as verbs

Note that the verb forms of these adjectives describe an emotional state, not an action, and are thus rarely used with continuous tenses:

• She wanted to please him, but disappointed him when he discovered that she had spent so much money. (NOT: … was disappointing him…)
  
  
• It surprises me to see you making so many basic errors in this game. (NOT: It is surprising me…)
  
  
• The novel interested me because it seemed to reflect real life so accurately.
  
  
• It amused me so much that I kept bursting out with laughter.

If you would like more practice more please visit our in the You, Me and Us part of our website.