Explanations:Phrasal verbs are an important aspect of English grammar, particularly in informal and conversational contexts. They consist of a verb combined with a preposition or adverb, and often have a meaning that is different from the individual words. In this case, the phrasal verb "ran into" is used to describe an unexpected meeting with someone.
The phrasal verb "ran into" is a separable phrasal verb, meaning that the object can be placed between the verb and the preposition. For example, "I ran my friend into" is also correct, although it is less common. The phrasal verb "ran into" is commonly used to describe a chance encounter, often with someone you know but have not seen in a long time.
Let's examine the other options to understand why they are incorrect:
Option A, "Came," is a simple verb that means to arrive at a place. It does not convey the idea of meeting someone, especially not an unexpected meeting. For example, "I came to the store" means you arrived at the store, but it does not imply that you met anyone there.
Option B, "Popped," can mean to appear suddenly, but it is not commonly used with "into" to describe a meeting. "Popped" is often used in phrases like "popped up" or "popped in," but these do not convey the same meaning as "ran into." For example, "I popped into the store" means you quickly went into the store, but it does not imply meeting someone.
Option C, "Met," is a general verb that means to come into the presence of someone. While it can be used to describe a meeting, it is too general and does not convey the idea of an unexpected meeting. "Met" can be used for planned meetings as well, which does not fit the context of the question. For example, "I met my friend at the park" implies a planned meeting, not an unexpected one.
Option D, "Ran into," is the correct answer because it is a phrasal verb that means to meet someone unexpectedly. It fits the context of the question perfectly, as it describes an unplanned encounter with a childhood friend. For example, "I ran into a childhood friend on the street yesterday" means you unexpectedly met a friend from your past while walking on the street.
Understanding phrasal verbs like "ran into" is crucial for mastering English grammar, especially in informal and conversational contexts. It is important to recognize the idiomatic meanings of phrasal verbs and use them appropriately in sentences to convey the intended meaning accurately.