Lecture Notes: Simple Past vs Present Perfect Tenses

Introduction

• Two common verb tenses for past actions in English: Simple Past and Present Perfect.
• Both are used for completed past actions.
• Objective: Understand the formation, usage, and time markers for each tense.

Formation of Verb Tenses

Simple Past

• Regular Verbs: Add "-ed" to the base verb.
• Irregular Verbs: Undergo various changes to the middle or ending of the verb.
• Negative Sentences and Questions: Use the auxiliary verb DID in front of the verb.

Present Perfect

• Formed by using the auxiliary verb HAVE or HAS plus the past participle form.
• HAVE becomes HAS with subjects HE, SHE, IT, or singular nouns.
• Regular Verbs: Add "-ed" to form the past participle.
• Irregular Verbs: Change form.
• Negative Sentences and Questions: Use the auxiliary verb HAVE or HAS.

Function of Tenses

Simple Past

• Used when the time of the past action is known.
• Example: "He went to school yesterday." (Time known: yesterday)

Present Perfect

• Used when the time of the past action is unknown.
• Example: "She has been to Brazil." (Time unknown)
• Can also indicate a past action continuing to the present (covered in another lesson).

Time Markers

Simple Past

• Necessary in sentences.
• Common markers: yesterday, the day before yesterday, last, ago.
• Examples: last week, a few weeks ago.

Present Perfect

• No time markers needed, but optional markers can be used for emphasis.
• Optional markers: already, still, yet, ever, never.

Examples and Practice

Affirmative Sentences

• Simple Past: "She watched a great show on TV last night." (Time marker: last night)
• Present Perfect: "He has read this book." (No time marker)

Negative Sentences

• Simple Past: "You didn't call me back yesterday." (Time marker: yesterday)
• Present Perfect: "Our house hasn't sold." (Optional markers: still, yet)

Questions

• Simple Past: "Did the neighbors get a new dog a few days ago?" (Time marker: a few days ago)
• Present Perfect: "Have you been to this restaurant?" (Optional markers: ever, yet)

Practice Sentences

1. "He didn't play baseball last weekend." (Time marker: last weekend)
2. "My sister hasn't bought a new car yet." (No specific past time, optional marker: yet)
3. "50 students have registered for this class." (No specific time mentioned)
4. "Have you ever traveled to South America?" (No specific time, optional marker: ever)
5. "Did you travel to South America last year?" (Time marker: last year)

Conclusion

• Understanding the difference between simple past and present perfect tenses.
• Use time markers to distinguish between the two.
• Practiced forming sentences with each tense.