Test Unit 7 (Past Perfect)

When the researcher arrived, the team ______ all the necessary data.

• had collected
• collected
• will collect
• has collected

Answer explanation

El past perfect (had + past participle) indica que la acción de recolectar ocurrió antes de la llegada del investigador.

The patient was feeling better because the doctor ______ a new treatment.

• will apply
• had applied
• applied
• has applied

Answer explanation

Usamos past perfect porque la acción de aplicar el tratamiento ocurrió antes de que el paciente se sintiera mejor.

By the time the lab technician arrived, the analysis ______.

• completed
• had been completed
• completes
• will complete

Answer explanation

Aquí se usa past perfect pasivo para destacar que el análisis ya estaba terminado antes de que llegara el técnico.

The equipment malfunctioned because no one ______ it properly.

• calibrated
• has calibrated
• had calibrated
• calibrate

Answer explanation

El past perfect indica que la falta de calibración ocurrió antes de que el equipo fallara.

After the experiment ______, the team prepared a detailed report.

• has finished
• will finish
• finished
• had finished

Answer explanation

Se usa past perfect porque la acción de terminar el experimento ocurrió antes de preparar el informe.

When the doctor checked the results, the lab technician ______ the slides.

• had prepared
• prepared
• prepares
• has prepared

Answer explanation

El past perfect muestra que los portaobjetos ya estaban listos antes de que el doctor revisara los resultados.

Once the biopsy ______, the pathologist examined the tissue.

• took
• has taken
• was taken
• had been taken

Answer explanation

Usamos past perfect pasivo para mostrar que la biopsia fue tomada antes del examen del tejido.

The researcher ______ the data before presenting the findings.

• analyzed
• analyzes
• had analyzed
• will analyze

Answer explanation

Past perfect se usa porque el análisis ocurrió antes de presentar los hallazgos.

By the time the meeting started, the lab technician ______ the report.

• will finish
• finishes
• had finished
• finished

Answer explanation

El past perfect indica que el informe ya estaba terminado antes de que comenzara la reunión.

The doctor realized there was contamination after the nurse ______ the pipette.

• has used
• used
• had used
• will use

Answer explanation

Past perfect muestra que la contaminación ocurrió después del uso de la pipeta.