Understanding the Sentence Context

The sentence "It ________ since yesterday" describes an ongoing action that began in the past and continues up to the present moment. The phrase "since yesterday" is a crucial time marker indicating the starting point of this continuous action.

Verb Tense Rules for Duration

To express actions that started in the past and are still continuing in the present, we use the Present Perfect Continuous Tense. The structure for this tense is:

• Subject + have/has + been + verb-ing (present participle)

The auxiliary verb 'has' is used with third-person singular subjects (like 'he', 'she', 'it'), while 'have' is used with other subjects ('I', 'you', 'we', 'they').

Analyzing the Verb Options

Let's look at each option provided:

• Option 1: has been raining
  This option uses the correct structure for the Present Perfect Continuous Tense with the third-person singular subject 'It' (using 'has'). It accurately conveys an action that started yesterday and is still happening now.
• Option 2: was raining
  This is the Past Continuous Tense. It describes an action that was in progress at a specific time in the past, but it does not imply continuation to the present. For example, "It was raining when I left the house." This doesn't fit "since yesterday".
• Option 3: is raining
  This is the Present Continuous Tense. It describes an action happening right now. While it might be raining now, the phrase "since yesterday" specifically points to the duration from a past point until now, making the Present Perfect Continuous Tense more appropriate.
• Option 4: have been raining
  This option uses the Present Perfect Continuous Tense structure but uses the auxiliary verb 'have'. 'Have' is incorrect with the third-person singular subject 'It'. The correct auxiliary verb should be 'has'.
• Option 5: (No verb form provided)
  This option is incomplete and cannot be evaluated.

Conclusion on Correct Verb Form

Based on the grammatical rules for expressing actions that began in the past and continue to the present, and considering the time marker "since yesterday", the Present Perfect Continuous Tense is required. Option 1, has been raining, correctly uses this tense with the appropriate auxiliary verb for the subject 'It'.