Test Unit 4 (Present perfect continuous)

1. How long _______ (you wait) for the results?

• have you been waiting
• have you waited
• are you waiting
• were you waiting

Answer explanation

Usamos el Present Perfect Continuous para acciones que empezaron en el pasado y continúan en el presente.

2. The researchers _______ (analyze) the data for hours.

• analyzed
• have been analyzing
• are analyzing
• have analyzed

Answer explanation

Usamos el Present Perfect Continuous para acciones recientes en progreso: "have been analyzing".

3. She _______ (study) for the exam since early morning.

• has been studying
• has studied
• is studying
• was studying

Answer explanation

Usamos el Present Perfect Continuous con "since" para enfatizar una acción en progreso desde un momento pasado específico.

4. We _______ (work) on this project all day.

• worked
• have been working
• were working
• have worked

Answer explanation

Usamos el Present Perfect Continuous para acciones recientes que se extienden en el tiempo: "have been working".

5. _______ (they prepare) the presentation for the conference?

• Have they been preparing
• Are they preparing
• Have they prepared
• Were they preparing

Answer explanation

En preguntas, el Present Perfect Continuous usa "Have/Has" + sujeto + "been" + verbo en "-ing".

6. The patient _______ (wait) for the doctor for 30 minutes.

• has been waiting
• has waited
• is waiting
• have been waiting

Answer explanation

Usamos el Present Perfect Continuous para acciones que continúan en el presente: "has been waiting".

7. I _______ (not feel) well for a couple of days.

• haven’t been feeling
• haven’t felt
• am not feeling
• haven’t been felt

Answer explanation

En la forma negativa, el Present Perfect Continuous usa "haven’t/hasn’t been" + verbo en "-ing".

8. They _______ (try) to fix the machine for the last two hours.

• have tried
• are trying
• have been trying
• tried

Answer explanation

Usamos el Present Perfect Continuous para acciones repetidas o continuas durante un período: "have been trying".

9. How long _______ (you use) this microscope?

• have you used
• are you using
• have you been using
• do you use

Answer explanation

Usamos el Present Perfect Continuous para acciones que comenzaron en el pasado y continúan.

10. The technician _______ (calibrate) the equipment since this morning.

• calibrated
• has been calibrating
• has calibrated
• was calibrating

Answer explanation

Usamos el Present Perfect Continuous con "since" para describir una acción en progreso desde un momento pasado.