The same as "present progressive". The tense is formed by combining the appropriate present tense form of "be" to agree with subject with the present participle of the other verb, and it indicates action or state of being continuing from at least the recent past through the present and into at least the immediate future. Example: "He is running fast", when one sees a runner in a race.
"IT is happen" does not mean anything; "it is happening" is a Present Tense - a Continuous Present Tense, to be more specific (not a "word").
The present continuous tense of stop is:I am stopping.He/She/It is stopping.You/We/They are stopping.
If you mean Present Continuous Tense here is what it is-We use the Present Continuous Tense to talk about activities happening now..ExamplesThe kids are watching TV. I am sitting down, because I am tired
The present continuous tense of lay:I am laying.You/We/They are laying.He/She/It is laying.
The present continuous tense of "do" is:I am doingWe are doingYou are doingHe/she is doingThey are doing
The present continuous tense:I am shying.You/We/They are shying.He/She/It is shying.
The present continuous tense of study is:I am studying.You/we/they are studying.He/she/it is studying.
There are five tenses: 1.simple present 2.present continuous 3.present perfect 4.present perfect continuous 5. present passive
I am lying.He/she/it is lying.You/we/they are lying.
The present continuous tense of 'precede' is:I am preceding.You/We/They are preceding.He/She/It is preceding.
The present continuous tense of 'believe' is:I am believingYou/We/They are believingHe/She/It is believing
Past perfect tense, past perfect continuous tense, present perfect tense, present perfect continuous tense, future perfect tense and future perfect continuous tense.