In the following error-spotting question, identify the part of the sentence that contains a grammatical error. If you turn the corner, (A) / you will found a house (B) / built of stone. (C) / No Error (D).

Introduction / Context:
This question checks your understanding of verb forms after modal auxiliaries in conditional sentences. The given sentence is “If you turn the corner, (A) / you will found a house (B) / built of stone. (C) / No Error (D).” You must identify which part of the sentence contains a grammatical error, if any. Such questions are common in exams to evaluate your accuracy in tense and verb usage.

Given Data / Assumptions:

• Part (A): “If you turn the corner,”
• Part (B): “you will found a house”
• Part (C): “built of stone.”
• Part (D): “No Error”
• The sentence is a first conditional: a likely future result if a condition is met.

Concept / Approach:
In a first conditional sentence, we generally use the present simple in the “if” clause and “will” plus the base form of the verb in the main clause. For example, “If you study, you will pass”, “If it rains, we will stay inside.” The structure “will” + verb must use the base form (find), not the past form (found). Therefore, “you will found a house” is incorrect; it should be “you will find a house”. The error lies in using “found” after “will”.

Step-by-Step Solution:
Step 1: Identify the conditional pattern: “If you turn the corner” indicates a present condition that may lead to a future result. Step 2: Recognize that the main clause starts with “you will …”, which requires the base form of a verb. Step 3: Note that “found” is the past tense of “find”, not the base form. Step 4: Recall the correct rule: after “will” we must use “find”, not “found”. Step 5: Conclude that Part (B) is incorrect and should be changed to “you will find a house”.

Verification / Alternative check:
Try reading the sentence with the corrected verb: “If you turn the corner, you will find a house built of stone.” This sounds natural and follows standard conditional structure. On the other hand, “you will found a house” is ungrammatical, because “found” is not used as a future form in this structure. Also, there is no reason to use the verb “found” in the sense of “establish” here; the context clearly implies discovering or coming across an existing house.

Why Other Options Are Wrong:
“Part (A)” with “If you turn the corner,” correctly uses present simple in the if-clause.
“Part (C)” with “built of stone.” is a correct past participle phrase describing the house.
“Part (D) No error” cannot be correct because we have already identified a clear mistake in Part (B).
“Whole sentence” is not an accurate choice because only the verb in Part (B) needs correction; the rest is fine.

Common Pitfalls:
Many learners accidentally use past forms of verbs after “will” or other modals, especially when the past form is more familiar. Another pitfall is confusing the verb “found” (establish) with the past tense of “find”. Remember that in future constructions like “will”, “shall”, “can”, “may”, the verb that follows must be in base form, such as “find”, “go”, “do”. Practice identifying conditional patterns to become more confident in choosing the correct verb forms.

Final Answer:
The grammatical error is in Part (B), which should be “you will find a house” instead of “you will found a house”.