A subseasonal weather forecast attempts to predict weather conditions three to four weeks in _______ its predictions are therefore more...

Let's begin by understanding the meaning of this sentence. We'll use our understanding of pause points and segment the sentence as shown - understanding and assimilating the meaning of each segment bit by bit!

Sentence Structure

• A subseasonal weather forecast
  • attempts to predict weather conditions
    • three to four weeks in advance[?]

• its predictions are therefore more short-term
  • than those of the seasonal forecast,
    • which attempts to predict the weather
      • more than a month in advance.

Understanding the Meaning

Let's start reading:

"A subseasonal weather forecast attempts to predict weather conditions three to four weeks in advance"

• This tells us what a subseasonal forecast does:
  • It tries to predict the weather 3-4 weeks ahead of time.

This is where we have the blank.

Let's look at the choices:

• We're deciding between different punctuation marks (comma, nothing, semicolon) or adding "and"

To see what works here, let's read the rest of the sentence and understand what it's saying!

"its predictions are therefore more short-term than those of the seasonal forecast, which attempts to predict the weather more than a month in advance."

Now let's understand what this is telling us:

• "its predictions are therefore more short-term"
  • This refers back to the subseasonal forecast
  • It's saying these predictions are relatively short-term

• "than those of the seasonal forecast"
  • Making a comparison to a different type of forecast
  • The seasonal forecast's predictions

• "which attempts to predict the weather more than a month in advance"
  • This describes the seasonal forecast
  • It tries to predict more than a month ahead

So the complete picture is:

• First part: subseasonal forecasts predict 3-4 weeks ahead
• Second part: these are more short-term than seasonal forecasts, which predict more than a month ahead

What do we notice about the structure here?

• The first part is a complete thought:
  • "A subseasonal weather forecast attempts to predict weather conditions three to four weeks in advance"
  • Subject: "A subseasonal weather forecast"
  • Verb: "attempts"
  • This could stand alone as a sentence

• The second part is also a complete thought:
  • "its predictions are therefore more short-term than those of the seasonal forecast"
  • Subject: "its predictions"
  • Verb: "are"
  • This could also stand alone as a sentence

• We have TWO complete sentences that are closely related
  • The second explains/elaborates on the first
  • The word "therefore" shows the logical connection

When we have two complete thoughts like this, we need proper separation.

The correct answer is C (semicolon).

A semicolon is the perfect punctuation mark to connect two complete, closely related sentences. It shows they're connected in meaning while properly separating them grammatically.

GRAMMAR CONCEPT APPLIED

Connecting Two Complete Thoughts

When you have two complete sentences (each with its own subject and verb, able to stand alone) that are closely related in meaning, you have several options:

Option 1: Semicolon

• Use when the thoughts are closely connected
• Example: "The storm arrived suddenly; residents had no time to prepare."
  • First part: complete sentence about the storm
  • Second part: complete sentence about residents
  • Semicolon shows they're related

Option 2: Period

• Use to fully separate the thoughts into two sentences
• Example: "The storm arrived suddenly. Residents had no time to prepare."

Option 3: Comma + Coordinating Conjunction

• Use comma plus FANBOYS (for, and, nor, but, or, yet, so)
• Example: "The storm arrived suddenly, so residents had no time to prepare."

What you CANNOT do:

• Just a comma = comma splice (run-on error)
• No punctuation = fused sentence (run-on error)

In our question:

• First complete thought: "A subseasonal weather forecast attempts to predict weather conditions three to four weeks in advance"
• Second complete thought: "its predictions are therefore more short-term than those of the seasonal forecast..."
• These are closely related (the second explains the first)
• Semicolon is the perfect choice to connect them