Tenses are fundamental grammatical tools that allow us to precisely indicate the time at which an action or state occurs. They help us understand whether something happened already, is happening now, or will happen later. Let's delve into the three basic tenses.

The Simple Present Tense is incredibly versatile and is used to describe actions that are routine, general truths, or scheduled events.

• Habitual Actions or Routines: This is its most common use. It refers to actions that occur regularly, repeatedly, or as a matter of habit.
• Example: I brush my teeth every morning. (A daily routine)
• Example: She goes to school on weekdays. (A regular activity)
• General Truths or Facts: It's used for statements that are universally true and unchanging.
• Example: The Earth revolves around the sun. (A scientific fact)
• Example: Water freezes at 0 degrees Celsius. (A general truth)
• Scheduled Events in the Near Future: This is particularly common for timetables, itineraries, or public transport schedules.
• Example: The movie starts at 7 PM. (A fixed schedule)
• Example: Our flight departs at dawn tomorrow. (A fixed timetable)
• To Give Instructions or Directions: In recipes, manuals, or directions.
• Example: First, you take a left, then you walk straight.
• Example: You mix the flour and sugar.

The Simple Past Tense is used to describe actions that were completed at a specific point in the past. The action started and finished entirely before the present moment.

• Actions Completed in the Past: This is the primary use. The time of the action is often specified or implied.
• Example: We visited the museum yesterday. (The visit is over)
• Example: She ate her dinner an hour ago. (The eating is complete)
• Example: They lived in London for five years. (They no longer live there)

Formation:
- Regular Verbs: For most verbs, we add '-ed' to the base form (e.g., walked, played, cooked, listened). If the verb ends in 'e', just add 'd' (e.g., loved, danced).
- Irregular Verbs: These verbs do not follow a simple rule and have unique past tense forms. These forms need to be memorized (e.g., go - went, see - saw, eat - ate, take - took, write - wrote).

The Simple Future Tense is used to describe actions that will happen at some point in the future. It expresses predictions, promises, or spontaneous decisions.

• Actions That Will Happen in the Future:
• Example: I will go to the market tomorrow.
• Example: They will start a new project next month.
• Predictions:
• Example: I think it will be sunny on Sunday.
• Example: The new movie will be a big hit.
• Spontaneous Decisions:
• Example: "I'm feeling cold." "I will close the window."
• Example: "Oh, the phone's ringing." "I will answer it."
• Promises or Offers:
• Example: I will help you with your homework.
• Example: We will meet you at the station.

Formation:
- The most common way to form the simple future is by using 'will' + the base form of the verb.
- Example: He will study. We will play. They will sing.

Articles are small but crucial words that precede nouns to specify whether the noun is definite (specific) or indefinite (non-specific). There are three articles in English: 'a', 'an', and 'the'.

Indefinite Articles: 'a' and 'an'
These articles are used when we are talking about a non-specific, general, or unidentified noun. They imply "one of many" or "any."

• 'a': This is used before words that begin with a consonant sound.
• Examples: a cat (k-sound), a table (t-sound), a car (k-sound).
• Crucially, it's about the sound, not just the letter. For example, "a university" (y-sound, not u-sound), "a unique idea" (y-sound), "a European country" (y-sound).
• 'an': This is used before words that begin with a vowel sound (a, e, i, o, u).
• Examples: an apple (a-sound), an elephant (e-sound), an ice cream (i-sound), an orange (o-sound), an umbrella (u-sound).
• Again, focus on the sound. For example, "an hour" (the 'h' is silent, so it starts with an 'o' sound), "an honest person" (silent 'h').

Definite Article: 'the'
'The' is the definite article. It is used when we are talking about a specific noun, one that is already known to the listener or reader, or when there is only one of that particular item.

• Referring to a Specific Item Already Mentioned or Understood:
• Example: I saw a dog. (The dog) was barking loudly. (First mention, then it becomes specific)
• Example: Can you pass me the salt? (It's clear which salt is being referred to, likely the one on the table).
• When there is only one of something in the world or in a specific context:
• Example: the sun, the moon, the Earth (when referring to the planet).
• Example: We visited the principal's office. (There's usually only one principal in a school).
• With Superlative Adjectives:
• Example: She is the smartest student in the class.
• Example: This is the best movie I've ever seen.
• Before Names of Rivers, Oceans, Seas, Mountain Ranges, Deserts, Groups of Islands, Famous Buildings, etc.:
• Example: the Nile, the Atlantic Ocean, the Himalayas, the Sahara Desert, the Bahamas, the Great Wall of China.
• When referring to unique groups or categories of people:
• Example: the poor, the rich, the elderly.
• Before Musical Instruments:
• Example: He plays the guitar very well.

Subject-verb agreement is a fundamental principle in English grammar stating that the verb in a sentence must match its subject in terms of number (singular or plural). If the subject is singular, the verb must be singular. If the subject is plural, the verb must be plural.

The Basic Rule:
- Singular Subject + Singular Verb:
- Example: The dog barks loudly. (Singular subject 'dog', singular verb 'barks' - verbs ending in 's' in simple present are singular)
- Example: She writes beautifully. (Singular pronoun 'she', singular verb 'writes')
- Plural Subject + Plural Verb:
- Example: The dogs bark loudly. (Plural subject 'dogs', plural verb 'bark' - verbs without 's' in simple present are plural)
- Example: They write beautifully. (Plural pronoun 'they', plural verb 'write')

Key Point: In the simple present tense, singular verbs (for the third person) typically end in '-s' or '-es', while plural verbs do not.