Marine biologists studying deep-sea ecosystems rely heavily on advanced sonar technology to map underwater terrain. A team at the Pacific...

Sentence Structure

• Marine biologists
  • studying deep-sea ecosystems
• rely heavily on advanced sonar technology
  • to map underwater terrain.

• A team
  • at the Pacific Research Institute
• has deployed a sophisticated sonar system
  • in the Mariana Trench.

• The system [?] underwater mountains, trenches, and volcanic formations
  • with remarkable precision.

• Where [?] = would have detected / detects / had detected / will have been detecting

Understanding the Meaning

Let's read from the beginning to understand what this passage is telling us.

The first sentence tells us:

• Marine biologists who study deep-sea ecosystems rely heavily on sonar technology
  • They use this technology to map underwater terrain
  • Notice the verb 'rely' is present tense - describing what marine biologists currently do

The second sentence gives us a specific example:

• A team at the Pacific Research Institute has deployed a sophisticated sonar system in the Mariana Trench
  • 'Has deployed' means they put this system in place, and it's currently there
  • The system is now operational

Now we reach the third sentence with our blank:

• 'The system _____ underwater mountains, trenches, and volcanic formations with remarkable precision.'

This is where we need to fill in the blank. Let's look at our choices:

• A. would have detected (conditional - hypothetical past)
• B. detects (simple present)
• C. had detected (past perfect)
• D. will have been detecting (future perfect continuous)

So we're choosing between different verb tenses. What timeframe makes sense here?

Let's think about what we know:

• The first sentence uses present tense to describe what marine biologists do
• The second sentence tells us the system 'has deployed' - meaning it's currently in place and operational
• The third sentence is describing what this operational system does

What do we notice about the structure here?

The passage establishes that:

• The system IS currently deployed and operational (from 'has deployed')
• We're describing what the system does as its current capability
• When describing what something currently does or is capable of doing, we use simple present tense

So we need: detects (choice B)

This makes sense: the system is currently in place, and we're stating what it does - it detects these underwater features. It's a statement of current fact and capability.

Grammar Concept Applied

Matching Verb Tense to Timeframe

When writing, you need to choose verb tenses that match the logical timeframe you're describing. Simple present tense is used to describe:

• Current facts and general truths
• Habitual or repeated actions
• Current capabilities of things

Example 1 - Current capability:

• The telescope observes distant galaxies with unprecedented clarity.
  • The telescope is operational now, and we're describing what it does
  • Simple present: 'observes'

Example 2 - After establishing something is in place:

• Scientists have installed new sensors in the Arctic. The sensors measure temperature changes hourly.
  • 'have installed' = present perfect (they're in place now)
  • 'measure' = simple present (what they currently do)

In our question:

• 'has deployed' establishes the system is currently operational
• 'detects' describes what this operational system currently does
• The simple present tense creates consistency: current operational status → current function

The other tenses (conditional perfect, past perfect, future perfect continuous) would create mismatches with the timeframe established by the context.