Every last second of space shuttle mission STS-79, which lasted ten days and three hours, ________ carefully monitored by a...

Sentence Structure

• Every last second
• of space shuttle mission STS-79,
• which lasted ten days and three hours,
• [?] carefully monitored by a team of experts.M/li>

Understanding the Meaning

Let's start reading from the beginning:

'Every last second of space shuttle mission STS-79...'

This is telling us about a specific space shuttle mission. The phrase 'every last second' emphasizes that we're talking about the entire duration - not just some moments, but literally every single second.

Now here's where we need to fill in the blank:

'Every last second... ______ carefully monitored by a team of experts.'

Let's look at our choices:

1. have been
2. are
3. was
4. were

We can see the choices differ in two ways - some are singular, some are plural, and they use different tenses.

What do we notice about our subject?

• The subject is 'every last second'
• The key word here is 'every' - which means each individual one
• 'Every' always takes a singular verb (just like 'each' does)
• Even though we're talking about many seconds in total, 'every second' treats them one at a time - individually

So we need a singular verb. That eliminates:

• A. have been (plural)
• B. are (plural)
• D. were (plural)

That leaves us with C. was (singular).

Now let's read the rest to see the complete picture:

'...which lasted ten days and three hours'

This tells us:

• The mission happened in the past (it 'lasted' - past tense)
• It was already completed
• So we need past tense to match this context

Perfect! 'Was' is both singular (to match 'every last second') and past tense (to match the completed mission).

The complete meaning: Every single second of this space shuttle mission that took place in the past was carefully watched by experts - they monitored the entire mission from start to finish.

GRAMMAR CONCEPT APPLIED

Subject-Verb Agreement with "Every" and "Each"

When a subject begins with "every" or "each," it always takes a singular verb - even if it seems like you're talking about multiple things (called a distributive in grammar terms):

Pattern:

• Every + singular noun + singular verb
• Each + singular noun + singular verb

Examples:

1. Every student in the three classes needs to complete the assignment.
   • Not "need" (plural)
   • "Every student" = singular, even though there are many students across three classes
2. Each of the paintings was created in a different year.
   • Not "were" (plural)
   • "Each" = singular
   • Don't be distracted by "of the paintings" - that's a prepositional phrase
3. Every last second of the mission was monitored.
   • Not "were" (plural)
   • "Every last second" = singular
   • The phrase "of space shuttle mission STS-79" separates the subject from the verb, but doesn't change the agreement

In this question:

• Subject: "Every last second" (singular)
• Verb needed: "was" (singular, past tense)
• The prepositional phrase "of space shuttle mission STS-79" and the relative clause "which lasted ten days and three hours" come between the subject and verb, but the agreement rule stays the same