**Rule**: The **Present Continuous Tense** is commonly used for future plans and arrangements, especially when they are confirmed. **Correct Usage**: 'is opening' describes a definite plan for the near future ('soon'). It implies that the arrangements for the opening are already underway. **Incorrect Options**: (a) 'opens' (Simple Present) is also possible as a scheduled event but is less common for a one-time event like this. (c) 'has opened' (Present Perfect) is for past events. (d) 'open' is the base form.

**Rule**: The **Present Perfect Continuous Tense** is used to emphasize the duration ('for the past six months') of a long project that is still in progress. **Correct Usage**: 'has been recording' correctly describes the continuous, ongoing work on the album over a long period. **Incorrect Options**: (a) 'records' (Simple Present) is a habit. (b) 'is recording' (Present Continuous) is for now. (d) 'has recorded' (Present Perfect) suggests the album is finished.

**Rule**: With verbs of perception like 'see', 'hear', 'smell', we often use **'can' or 'can't' + base verb** instead of the Present Continuous to describe what is or isn't perceived at the moment. **Correct Usage**: 'can't hear' is the most natural and common way to express the inability to hear something at the present moment. **Incorrect Options**: (b) 'am not hearing' is grammatically incorrect as 'hear' is a stative verb. (c) 'haven't heard' (Present Perfect) refers to the past. (d) 'don't hear' (Simple Present) refers to a general inability.

**Rule**: The **Present Perfect Tense** is used to describe a state or situation in an unfinished period of time ('so far'). **Correct Usage**: 'has been' correctly describes the quality of the party from the beginning up to the present moment. **Incorrect Options**: (a) 'is' (Simple Present) only describes the party right now. (c) 'is being' would mean the party is actively behaving terribly. (d) 'was' (Simple Past) would mean the party is over.

**Rule**: The **Present Perfect Tense** is used to ask about a recent past action that has a clear result in the present ('You look very pleased'). **Correct Usage**: 'What have you done?' is the correct question to ask about the cause of the person's current happy state. **Incorrect Options**: (a) 'do, do' (Simple Present) is a habit. (b) 'are, doing' (Present Continuous) is for now. (c) 'have, been doing' asks about a continuous activity, but the result suggests a single, completed action.

**Rule**: The **Present Continuous Tense** is used for an action that is in progress at the time of speaking. **Correct Usage**: The speaker's request 'Don't turn off the TV!' clearly indicates that the action of watching is happening right now. Therefore, 'am watching' is the correct choice. **Incorrect Options**: (a) 'watch' (Simple Present) describes a habit. (c) 'have watched' (Present Perfect) means the action is finished. (d) 'have been watching' (Present Perfect Continuous) implies a duration, which is not the main point here.

**Rule**: **Stative Verbs**. The verb 'smell' is stative when describing a quality. It is used in the **Simple Present Tense** to describe a current state. **Correct Usage**: 'smells' correctly describes the current quality of the milk. The subject 'The milk' is singular. **Incorrect Options**: (b) 'is smelling' is incorrect because 'smell' is stative here. (c) 'has smelled' is the wrong tense. (d) 'smell' is a plural verb.

**Rule**: The **Present Continuous Tense** is used to talk about fixed plans for the future, especially personal or professional life events. **Correct Usage**: 'is retiring' correctly describes the professor's definite plan for next year. **Incorrect Options**: (a) 'retires' (Simple Present) is also possible but less common for a personal plan. (c) 'has retired' (Present Perfect) is for a past retirement. (d) 'retire' is a plural verb.

**Rule**: The **Present Perfect Tense** is used to announce recent news or a recently completed event. **Correct Usage**: 'has reported' correctly communicates the recent news of the breakthrough. 'Team' is treated as a singular unit. **Incorrect Options**: (a) 'reports' (Simple Present) is a habit. (b) 'is reporting' (Present Continuous) is for now. (d) 'report' is a plural verb.

**Rule**: **Subject-Verb Agreement** with indefinite pronouns. 'Either' is a singular indefinite pronoun and requires a singular verb. Also, 'seem' is a **stative verb** and is not used in the continuous form. **Correct Usage**: The singular verb 'seems' agrees with the singular subject 'Either'. **Incorrect Options**: (a) 'seem' is a plural verb. (b) 'are seeming' is incorrect both because it's plural and because 'seem' is stative. (d) 'have seemed' is plural and the wrong tense.