1. Because it was a rainy day, he took an umbrella with him.

2.Because it was a rainy day, he took an umbrella.
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Do we have to use 'with him' as in the first sentence? How about #2? What is the difference between Sentence 1 and Sentence 2?

Both sentences are fine. They seem to mean the same thing. The only difference between them is the prepositional phrase "with him" but it's rather redundant!

However, depending on the context, the second sentence COULD mean that he stole an umbrella! The word "took" is sometimes used as a substitute for "stole."

In English, both Sentence 1 and Sentence 2 convey the same meaning, but there is a slight difference in emphasis.

1. "Because it was a rainy day, he took an umbrella with him."
In this sentence, the phrase "with him" is added to emphasize that he took the umbrella along with himself. It suggests that he carried the umbrella physically, perhaps holding it or putting it in his bag. The "with him" phrase makes it clear that the umbrella was in his possession, ensuring he had it readily available.

2. "Because it was a rainy day, he took an umbrella."
In this sentence, the phrase "with him" is omitted. While it is still understood that he took the umbrella for his own use, the absence of "with him" implies that he took the umbrella without explicitly indicating where he put it, or whether he physically carried it. It could be interpreted as he might have left the umbrella in a nearby location, like in his car or at the office, as long as he had access to it when needed.

Both sentences are grammatically correct and convey the same overall meaning. The choice between them depends on the specific context and the degree of emphasis or clarity desired.