Is the word "beginning" here a gerund or a present participle, and why?
On June 22, 1941, the armies of Nazi Germany crossed the Soviet border, beginning a war that would claim the lives of millions of soldiers and civilians alike.
Is the word "beginning" here a gerund or a present participle, and why?
On June 22, 1941, the armies of Nazi Germany crossed the Soviet border, beginning a war that would claim the lives of millions of soldiers and civilians alike.
It may help to untangle things if you separate the form of the word and its function. Beginning is a present participle, no matter how it's used. You can tell because it's the plain form of the verb (the part after to in the infinitive) with the suffix -ing appended. Participles have three functions in a sentence:
The Germans were beginning a war.
Beginning the war was part of German strategy.
The country beginning the war was Germany.
When the participle functions as a noun, we call it a gerund. Most often when the participle functions as a modifier, it does so like an adjective, i.e., modifying a noun. In example 2 above, beginning tells us who did the beginning. But the participle can also have adverbial uses, modifying the verb:
3a. Germany began the war, sending panzers across their border with Poland.
Here the participle tells us, at least in part, how the Germans began the war. When the participial phrase is introductory, it may be unclear what it's modifying:
3b. Sending panzers across their border with Poland, Germany began the war.
Here sending tells which Germans we're talking about and how they did what they did. This is called an absolute construction, implying that it is independent of the main clause.
The clause with "beginning" corresponds to "and thereby they began a war ...". If you want to shorten such a second clause you need a participle. You can replace "and thereby they were beginning a war..." by the shorter "beginning a war ..."
You have a gerund in a sentence like: Beginning a war with Russia lead to a disaster. Here you could think: "The beginning of a war with Russia ..." to get a feeling for the noun-character of the gerund. (The gerund has noun- and verb-character).
The present participle is formed by adding -ing to the ... infinitive verb stem. ... It may act as a noun (gerund), adjective, nonfinite verb, or as an adverb with the use of a participle phrase. [The Chicago Manual of Style]
All infinitives altered to form an -ing ending are present participles. It becomes a gerund if it's a noun.
Your example looks like a verb to me. [What do they do? Begin a war--an action]
You could force the noun by altering to "the beginning of a war ... ."