What is It ?
It is pron 1. used to show something which has just been mentioned What do you want me to do with the box? – Put it down. Where’s the box? – It’s here. She picked up a potato and then dropped it on the ground. I put my book down somewhere and now I can’t find it. Where’s the newspaper? – It’s on the chair. The dog’s thirsty, give it something to drink. 2. referring to no particular thing Look! – it’s snowing. It’s miles from here to the railway station. Is it the 30th today? It’s almost impossible to get a ticket at this time of year. What time is it? – It’s ten o’clock. It’s dangerous to use an electric saw when it’s wet. (NOTE: It’s = it is or it has. Do not confuse with its.)
source: Easier English, Student Dictionary Upper Intermediate Level