Understanding the Sentence and Underlined Segment

The sentence is "The flames had shot up higher then never." We need to examine the underlined part "then never" and see if it correctly fits the grammar and meaning of the sentence, especially considering the use of the comparative word "higher".

The word "higher" is the comparative form of "high". When we use comparative words like "higher," we typically make a comparison between two things or states. The structure usually involves "comparative adjective/adverb + than + something."

Analyzing the Original Phrase "then never"

Let's break down the phrase "then never":

• Then: This word is usually used to indicate sequence in time (e.g., "first this, then that") or as a result (e.g., "if that is true, then...").
• Never: This means at no time.

Combining "then" with a comparative structure and "never" does not form a grammatically correct or meaningful comparison in standard English. The sentence is trying to say the flames reached a greater height compared to any previous time.

Evaluating the Options for Substitution

Let's look at the provided options:

1. than ever: This option uses "than," which is the correct word for comparison with "higher". "Ever" means at any time. The phrase "higher than ever" is a standard idiom meaning higher than at any time in the past. This fits the likely intended meaning of the sentence.
2. than never: This option uses "than" correctly for comparison, but "never" is not a suitable point of comparison here. "Higher than never" doesn't convey a logical meaning.
3. No substitution: As established, the original phrase "then never" is grammatically incorrect and should be substituted.
4. then ever: This option uses "then," which is incorrect for making a comparison. It should be "than".

Identifying the Correct Substitution

Based on the analysis, the phrase that correctly uses the comparative structure and conveys the intended meaning (flames reaching an unprecedented height) is "than ever". This is a common and correct English idiom.

Detailed Explanation

The sentence requires a comparative structure after "higher". The correct conjunction for comparison is "than". Therefore, options using "then" (the original and option 4) are incorrect.

We are left with "than ever" and "than never". The phrase "higher than ever" means the height is greater than it has been at any point in the past. This makes perfect sense in the context of flames shooting up.

The phrase "higher than never" is nonsensical. You cannot be higher than "no time".

Therefore, "than ever" is the appropriate and correct substitution for the underlined segment "then never".

Conclusion

The correct substitution for "then never" is "than ever" to form the grammatically sound and meaningful sentence: "The flames had shot up higher than ever."

Revision Table: Understanding Comparative Structures

Here's a quick review of comparative forms:

• Use "than" to introduce the second part of a comparison (e.g., taller than, faster than, more beautiful than).
• "Then" is used for sequence (e.g., first A, then B) or consequence (e.g., if X, then Y).
• The idiom "comparative adjective/adverb + than ever" means something is more [adjective/adverb] than it has been at any previous time.

Additional Information: Common Grammar Confusions

The confusion between "than" and "then" is very common. Remember these simple rules:

• Than: Comparison (think 'a' for comparison) - e.g., taller than, less than.
• Then: Time/sequence (think 'e' for time/event) - e.g., first... then..., at that time then.

Another related confusion involves "ever" vs. "never". "Ever" means at any time, while "never" means at no time. When comparing a current state to all past times in a superlative sense (which "higher than ever" implies), "ever" is the correct choice.