Fill in the blank with the correct infinitive: It's___________ the piano.

- We often use it + be followed by an adjective to give opinions.
- We use the to-infinitive with these adjectives to give opinions about people:

Examples:
It's easy to play the piano, but it's very difficult to play well.
He spoke so quickly that it was impossible to understand him.

আরো যে, adjective গুলোর পরে, to-infinitive বসে, সেগুলো হল: 
Clever, Foolish, Nice, Right, Difficult, Hard, Easy, Kind, Impossible, ইত্যাদি। 


Source: British Council Learning website.