In this error-spotting question, identify which part of the sentence contains an error: "They are looking forward (A) / to meet (B) / their parents (C) / No Error (D)".

Introduction / Context:
This error-spotting question checks your knowledge of verb patterns that follow certain fixed expressions. The sentence reads "They are looking forward (A) / to meet (B) / their parents (C) / No Error (D)." The phrase "looking forward to" is very common, but the form of the verb that follows "to" in this expression is often misused. Spotting this type of error requires familiarity with gerund usage.

Given Data / Assumptions:

• Part A: "They are looking forward".
• Part B: "to meet".
• Part C: "their parents".
• Part D: "No Error".
• The intended meaning is that they are eagerly waiting to see their parents.

Concept / Approach:
The expression "look forward to" is always followed by a gerund (verb plus ing) or a noun, not by a bare infinitive. Correct examples include "looking forward to meeting you" and "looking forward to the holidays." The "to" in this phrase is a preposition, not the "to" of the infinitive. Therefore, the correct form after "to" is "meeting," not "meet." This means the error occurs in part B of the sentence.

Step-by-Step Solution:
Step 1: Recognise "are looking forward" in part A as the present continuous form of the phrasal verb "look forward," which is correct.Step 2: Recall the pattern "look forward to" plus gerund or noun.Step 3: Examine part B "to meet" and note that "meet" is the base form, not the gerund "meeting."Step 4: Identify this as a violation of the required pattern; it should be "to meeting."Step 5: Check part C "their parents," which correctly completes the object of "meeting" and has no error.Step 6: Conclude that part B is the incorrect segment and must be marked as the error.

Verification / Alternative Check:
Rewrite the sentence correctly as "They are looking forward to meeting their parents." This version is idiomatic and grammatically correct. If we keep "to meet," the sentence sounds wrong to a native speaker. You can also compare with other standard examples: "I am looking forward to seeing you," not "to see you." These comparisons confirm that the correct structure always uses the gerund after "looking forward to."

Why Other Options Are Wrong:
Part A uses the correct progressive form "are looking forward" and contains no error. Part C "their parents" is a correct noun phrase serving as the object of "meeting" in the corrected sentence. Part D "No Error" would imply that nothing is wrong in the sentence, which is not true because part B uses the wrong verb form. Therefore, A, C and D cannot be the correct answer.

Common Pitfalls:
Many learners assume that any "to" before a verb indicates the infinitive and therefore write "to meet," "to go" or "to see" after similar expressions. However, some expressions use "to" as a preposition, which must be followed by a gerund or noun. Examples include "look forward to," "be used to," and "admit to." Remembering these fixed patterns and practising them in sentences will help you avoid this frequent exam trap.

Final Answer:
The error is in part B; it should be "to meeting," so the correct answer is B.