Test Unit 3 (Present Perfect)

1. _______ you ever _______ (work) in a laboratory?

• Has, worked
• Have, work
• Have, worked
• Has, work

Answer explanation

En preguntas en Present Perfect, usamos "Have/Has" + sujeto + participio pasado.

2. The researchers _______ (not finish) their report yet.

• haven’t finished
• hasn’t finished
• don’t finish
• not finished

Answer explanation

Para negativos, usamos "haven’t/hasn’t" seguido del participio pasado.

3. _______ he _______ (analyze) the samples already?

• Have, analyzed
• Has, analyzed
• Does, analyze
• Did, analyze

Answer explanation

En preguntas afirmativas con "he", usamos "Has" + participio pasado: "Has he analyzed".

4. We _______ (just complete) the test.

• has just completed
• have just completed
• just completed
• have just complete

Answer explanation

En afirmativas, usamos "Have/Has" + "just" + participio pasado.

5. They _______ (already publish) their findings in a journal.

• has already published
• already publish
• have already published
• have published

Answer explanation

Para sujetos plurales como "they", usamos "have" + participio pasado.

6. The technician _______ (not calibrate) the equipment yet.

• not calibrated
• haven’t calibrated
• doesn’t calibrate
• hasn’t calibrated

Answer explanation

Para negativos en tercera persona singular, usamos "hasn’t" + participio pasado.

7. _______ you _______ (test) the new equipment?

• Does, tested
• Did, test
• Have, tested
• Has, tested

Answer explanation

En preguntas afirmativas con "you", usamos "Have" + participio pasado: "Have you tested".

8. She _______ (never work) in this field before.

• have never worked
• hasn’t worked
• never works
• has never worked

Answer explanation

Para afirmativas con "she", usamos "has" + "never" + participio pasado.

9. We _______ (complete) three experiments this week.

• have completed
• completed
• has completed
• have complete

Answer explanation

En afirmativas, usamos "Have/Has" + participio pasado.

10. The team _______ (not finish) analyzing the data.

• didn’t finish
• haven’t finished
• has not finished
• hasn’t finished

Answer explanation

Para negativos en plural como "the team", usamos "haven’t" + participio pasado.